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 BOUGHT WITH THE INCOME OF THE 
 
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 HENRY W. SAGE 
 
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Cornell University 
 Library 
 
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 the United States on the use of the text. 
 
 http://www.archive.org/details/cu31924004063644 
 
PLATE I. 
 
 Earth Pillar — Allt Dearg, Fochabers. 
 
MEMOIRS OF THE GEOLOGICAL SURVEY. 
 
 SCOTLAND. 
 THE GEOLOGY 
 
 OF 
 
 LOWER STRATHSPEY 
 
 (Explanation of Sheet 85.) 
 
 BY 
 
 L. W. HINXMAN, B.A., F.E.S.E. 
 
 AND 
 
 J. S. GRANT WILSON 
 
 WITH 
 
 Petrological Chapter and Notes by 
 J. S. FLETT, M.A., M.B., CM., D.Sc. 
 
 PUBLISHEB BV order OF THE LORDS COMMISSIONERS OF HIS MAJESTY S TREASURY. 
 
 GLASGOW: 
 
 PRINTED FOR HIS MAJESTY'S STATIONERY OFFICE 
 
 By JAMES HEDDERWIOK & SONS, 
 
 At " The Citizen Press," St. Vincent Place. 
 
 And to be purchased from 
 JOHN MENZIES & Co. , Bose Street, Edinburgh ; 
 
 E. STANFORD, 12, 13, and 14, Long Acre, London ; 
 
 HODGES, FIGGIS & Co., Ltd., Grafton Street, Dublin ; 
 
 From any Agent for the sale of Ordnance Survey Maps ; or through any 
 
 Bookseller from the Ordnance Survey Office, Southampton. 
 
 1902. 
 Price One Shilling and Sixpence. 
 
PREFACE 
 
 This memoir describes the geology of the area included in Sheet 
 85 of the one-inch map of Scotland, which embraces the district of 
 Lower Strathspey and adjacent tracts in the counties of Elgin, Banff, 
 and Aberdeen. The ground was originally mapped by Mr. Hinxman, 
 Mr. J. S. Grant Wilson, and Mr. Linn, and at a subsequent date 
 the area occupied by the Banffshire series of the crystalline schists, 
 in the south-east part of the Sheet, was re-examined by Mr- 
 Wilson. 
 
 Dr. Flett has contributed a chapter (Chapter VII.) on the petro- 
 graphy of the plu tonic masses and certain types of the metamorphic 
 rocks, and on the contact metamorphism produced by the igneous 
 intrusions. While preparing his materials he visited the area for 
 the purpose of studying some of the phenomena in the field. 
 
 Special thanks are due to Dr. Traquair, F.R.S., for his report on 
 the fossil fishes of the Old Eed Sandstone of Scotland, and the list 
 of the fishes found at Scaat Oraig-^ to Mr. E. Kidston, F.R.S., for 
 his notes on the fossil plants of the Old Red Sandstone of Scotland ; 
 and to Mr. Tajdor, I/hanbryde, near Elgin, who has supplied a list 
 of the fishes found by him at various localities in that formation in 
 the Sheet. 
 
 ' The three Plates ^ave been prepared from photographs taken by 
 Mr. Lunn, of the Geological Survey, and the Bibliography given in 
 the Appendix has been compiled By Mr, Hinxman. 
 
 The manuscript has, been edited by Mr. Home. 
 
 J. J. H. TEALL, 
 
 Director. 
 Geological Survey Office, 
 
 London, 16th January, 190S. 
 
CONTENTS. 
 
 PAGE. 
 
 Peepace, iii 
 
 CHAPTER I. 
 
 Area Embraced in the Map. Form of the Ground, Hills, Kiver 
 
 Systems, Lakes, 1 
 
 UHAtTER II. 
 
 Geological Features and Surface Kelief . Features due to outcrop 
 of different rocks — to faulting — to glacial action. Drainage 
 system — age of river-valleys. Geological structure in 
 relation to Population and Economics, 3 
 
 CHAPTER III. 
 
 Formations and Groups of Rock. General Geological Structure 
 
 of Area, 9 
 
 CHAPTER IV. 
 Metamoephic Rocks — Banffshire Series, 12 
 
 Quartzite — Limestone — " Black Schist " — Mica Schist, Clay 
 Slate, and Phyllite. 
 
 CHAPTER V. 
 
 Granulitic Schists of the Central Highlands, 24 
 
 Nomenclature — general lithological character and structure — 
 description of typical sections. 
 
 CHAPTER VI. 
 Igneous Rocks, 29 
 
 Principles of Classification — Older Plutonic masses — Epidio- 
 rites, Gabbro, and Serpentine — Foliated Granite. Newer 
 Plutonic rocks — Ben Rinnes Granite — differentiation of 
 original magma — intermediate and basic modifications — 
 correlation with Cairngorm Granite mass — Mica Diorite. 
 Later Lamprophyre Dykes. 
 
 CHAPTER VII. 
 
 Peteogeaphy of the Aeea, 36 
 
 Later Granites and Diorites. Earlier (foliated) Igneous Rocks 
 — Metamorphic Rocks of Sedimentary Origin — Effects of 
 Contact Metamorphism. 
 
 CHAPTER VIII. 
 
 The Old Red Sandstone— general distribution. Middle or 
 Orcadian Series — main masses — outliers — contemporaneous 
 andesite. Upper Old Red Sandstone— distribution — fossil 
 evidence — section at Scaat Craig, 58 
 
VI CONTENTS 
 
 OHAPTEK IX. PAGE. 
 
 Glacial and Recent Deposits, 65 
 
 Direction of principal ice-movements. Erratic blocks — of 
 western area — northern area — east of the Spey. Local 
 dispersion of Diorite boulders. Boulder clay. Pre-glacial 
 Valley of AUt Arder. Fluvio-glacial Sands and Gravels. 
 Glacial Lakes. Moraines. River alluvial deposits. Basin 
 Peat. Hill Peat. 
 
 CHAPTER X. 
 
 Economic Products, - 74 
 
 Limestones — analyses of. Roads, Highways, and Road-metal. 
 Building-stone. Roofing-slate. Brick-clay. Mineral wells. 
 
 Ironstone. 
 
 APPENDIX. 
 
 Part I. Palseontological — Notes on the Fossil Fishes and Plants 
 
 of the Old Red-Sandstone of Scotland, 81 
 
 Part II. List of Papers referring to the Geology of the Region 
 
 under description, ' 84 
 
 Part III. List of Microscopic Sections prepared from Rocks 
 
 collected in Sheet 85, 86 
 
 LIST OF ILLUSTRATIONS. 
 
 Plate I. Earth Pillar, Allt Dearg, Fochabers, Frontispiece. 
 
 „ II. Pre-glacial Valley, Allt Arder, Knockando; Fluvio- \ To face 
 
 glacial Sands and Gravels resting on Boulder-clay, J p. 66 
 ,, III. Sands and Gravels resting on Red Boulder-clay, OlifF 
 
 above River Spey, opposite Rothes, 68 
 
 Fig. 1 . Corroded hornblende filled with Quartz ; Quartz-diorite ; 
 
 Netherly, Burn of Rothes, Elgin, 41 
 
 ,, 2. Graphic inter-growth of quartz and cordierite ; Cordierite 
 
 hornfels ; Netherly, Bum of Rothes, Elgin, 52 
 
 „ 3. Chiastolite in chiastolite-slate ; Aidwell Inn, Banffshire, 55 
 
EXPLANATION OF SHEET 85. 
 
 CH4PTER I. 
 
 Area Embraced in the Map. — The district represented in Sheet 
 85 of the Geological Survey Map of Scotland includes an area of 
 432 square miles, almost equally divided between the counties of 
 Elgin and Banff, vyhich lie on either side of the river Spey. 
 Charleston-of-Aberlour may be regarded as the centre of the map, 
 which extends in the north from Newmill westwards to the village 
 of Eafford, and in the south from the Black Hill near the Lower 
 Cabrach to Dalliefure on the Spey. 
 
 Form of the Ground. — The highest ground in the area is found 
 in the south and south-west, whence the surface of the country falls 
 northwards to the shores of the Moray Firth. 
 
 The dominant feature of the district is the granite mass of Ben 
 Kinnes and the Convals. The long ridge of Ben Einnes, crowned 
 with rock-masses locally known as "scurrans"((?aeZ'ic sgoran), rises 
 gradually to a height of 2755 feet at its eastern extremity, and 
 from its isolated position forms a well-known landmark over a vast 
 extent of country. Another tract of high ground, with summits 
 ranging from 1500 to over 2000 feet, borders the area in the south, 
 and extends westwards from the hills of the Glen Fiddich Forest to 
 the northern spurs of the Cromdale range which divides the Avon 
 Valley from Strathspey. A third hilly region of lower elevation 
 forms the watershed between the Spey and Lossie, and extends far 
 to the north-east in a wide expanse of rolling moorland with a mean 
 elevation of over 1000 feet, that falls gradually northwards to the 
 cultivated lowlands of the Laigh of Moray. Separated from this 
 high plateau by the valleys of the Spey and Lossie, are such isolated 
 eminences as the quartzite peak of Ben Aigan, above Craigellachie 
 — 1544 feet ; and the long ridges of Eildon Hill and the Hill of 
 the Wangie, which rise with steep faces to the south above the 
 valleys of the Lossie and the Black Burn. The country between 
 the Deveron and Isla and to the north and north-west of Keith is 
 undulating, and broken into low hills and valleys. The smooth 
 rounded hilltops are clothed with wood or heather, while the slopes 
 and valley-bottoms are entirely under cultivation. 
 
 EiVER Systems. — The chief drainage-system is that of the Spey 
 and its tributaries, fully two-thirds of the area being included 
 A 
 
2 Explanation of Sheet 85. 
 
 within the basin of that river, which crosses the centre of the sheet 
 from south-west to north. On the right bank it receives at Ballin- 
 dalloch its most important tributary, the Avon, a small portion 
 only of whose course falls within this map, and lower down it is 
 joined by the Kddich at Craigellachie. On the left bank there 
 are many smaller affluents, such as the Tulchan Burn, the Allt 
 Gheallaidh, and other streams flowing off the southern slopes of the 
 Elginshire moorlands. The north-west portion of the area is 
 drained by the river Lossie, the eastern borders by the Isla and the 
 Deveron. 
 
 Lakes. — Loch Dallas, Loch Noir, and other smaller pools, all of 
 which occupy shallow hollows in the drift-covered moorlands round 
 the head waters of the Lossie, are the only natural pieces of water 
 in the map. Many of the depressions in the sheet of gravel that 
 extends to the north and south of Eafford were also at one time 
 occupied by small shallow lochans. These have now disappeared, 
 either through drainage operations or by natural silting up and 
 vegetable growth filling their beds. L. W. H. 
 
Geological Feahcres and Surface Belief. 
 
 CHAPTEE II. 
 
 Geological Features and Surface Belief. 
 
 An examination of the map will at once show the influence of 
 the geological structure on the features of the country. The hills 
 and higher ridges in the south and south-east have been determined 
 by the outcrop of the harder quartzite masses, and follow the 
 direction of their strike ; while the valleys have been excavated 
 along the bands of softer slates and phyllites of the Banffshire 
 series. 
 
 The central granite protrusion gives rise at once to the most 
 prominent features and to the highest mountain in the district; the 
 lofty peak of Ben Einnes, the rounded forms of the two Convals, 
 and the ridge of the Hunt Hill on the north side of the Spey being 
 due to the unequal wasting of this mass of igneous rock. The 
 high-level moorland plateau between the Spey and the Lossie is 
 formed from the quartzo-micaceous schist and flagstone series, and 
 owes its smooth contours and more or less featureless character to 
 the comparative homogeneity and equal weathering of these rocks. 
 The chain of hills that runs northwards from Craig an Tarmachain 
 on the south edge of the sheet to Cragganmore is a higher part of 
 this plateau, isolated by the deep valleys of the Avon and the 
 Spey. Ben Aigan is another isolated eminence formed by an outlying 
 mass of hard quartzite surrounded by softer rocks, while to the 
 incoherent conglomerates and soft sandstones along the northern 
 border are due the fertile lowlands that descend to the seaboard of 
 Moray. 
 
 The only prominent feature due to faulting is the straight 
 trench-like hollow that extends from Dufftown past Eothes nearly 
 to the edge of the sheet. It coincides with a dislocation running 
 N.N.W. and S.S.E. with a downthrow to the K, and has defined 
 the lower valley of the Fiddich, the course of the Spey between 
 Craigellachie and Eothes, and the deep glen of Eothes through which 
 now passes the railway to Elgin. 
 
 The elements of surface-relief due to glacial action are chiefly 
 those of accumulation rather than of erosion. The original features 
 of the surface are to a large extent softened and modified by the 
 drift deposits which lie thickly in the valleys, swathe the hillsides, 
 and sweep over the cols, leaving only the higher hilltops bare of 
 superficial covering. Erosive action may, on the other hand, be 
 traced in the rocky faces that are occasionally found low down 
 on the sides of the wider river valleys, as at the Craigs of Callander, 
 at Tulchan, and at Culfoichmore, in Strathspey. These may be 
 
4 Explanation of Sheet 85. 
 
 ascribed to the action of the later valley glaciers, which have swept 
 out the deposits of an earlier ice" sheet from the bottom of the 
 valley, leaving bare the projecting parts of the lower hill slopes. 
 It is noticeable that these rock-surfaces are most frequent where 
 the hillsides are steep and there is a certain amount of constriction 
 in the valley — that is at the points where the ice would exert the 
 greatest abrading force. 
 
 Many of the smaller tributary valleys have been completely 
 filled with glacial deposits, through which the present stream is now 
 cutting a new channel. An excellent example of such a drift-filled 
 pre-glacial valley is seen along the Allt Arder, north of Ballindalloch 
 {see Chap. IX.). 
 
 The drainage system of a country composed of intensely plicated 
 metamorphic rocks such as occupy the western portion of this area 
 may be expected to be a complex one, in which the laws which 
 govern the flow of streams through comparatively homogeneous 
 and undisturbed strata will be considerably modified. We there- 
 fore find that the valley of the Upper Spey is to a large extent 
 inconsequent, that is, independent of the strike and inclination of 
 the rocks through which it passes. The lower course of the Avon 
 is, on the other hand, for a long distance approximately parallel to 
 the strike of the rocks, and has probably been determined by the 
 outcrop of a" band of felspathic flagstones softer in nature than the 
 more siliceous strata that form the hills on either side of the river 
 valley. 
 
 Further anomalies found in the east and south-east parts of the 
 district are due to the fact that the present drainage system is in 
 part a superimposed one, and caused by an uplift of strata of Old 
 Eed Sandstone age.- These rocks may at one time have covered 
 nearly the whole area, but have since been removed by denudation- 
 except along the northern margin of the sheet. 
 
 The position of certain outlying fragments of this' once wide- 
 spread covering affords direct evidence that many of the river 
 valleys are of pre-Old-Eed-Sandstone age, and were originally 
 determined by the nature and distribution of the various members 
 of the metamorphic series. Patches of sandstone and conglomerate 
 occur at several points along the courses of the river Lossie and 
 the Black Burn, between whose parallel valleys the ridge of 
 schistose rocks that forms the Hill of the Wangle rises to a height 
 of 400-600 feet above the present valley-level. Another striking 
 instance is found on the headwaters of the river Isla, near the 
 farm of Upper Towie, about four miles south-west of Keith. The 
 stream here flows for some distance over a floor of conglomerate 
 which fiUs up the bottom of a deep valley excavated in the black 
 schist. The small patch of conglomerate upon which rest the piers 
 of the railway viaduct that crosses the Fiddich near Dufftown is 
 again the last relic of a mass of Old Eed Sandstone that at one 
 time filled the valley of that river. Similar evidence as to the age 
 of the valley of the Tervie Burn is afforded by the small area of 
 conglomerate seen along the stream side at Craighead, close to the 
 southern margin of the map. This valley has also been carved 
 
Geological Features and Surface Relief. 5 
 
 out of the softer rocks of the Banffshire series between two ridges 
 of quartzite, of which that on the north side rises to a height of 
 1000 feet above the bottom of the valley. 
 
 The Deveron, Fiddich, DuUan Water, and Isla, that drain the 
 area occupied by the Banffshire series, were thus at one time con- 
 sequent streams as regards this covering of Old Eed Sandstone that 
 dipped towards the north. They now follow the strike of the 
 underlying schists, and are thus subsequent with respect to the 
 rocks thatformthepresent surface of the country. Their present north- 
 east course is probably a modification of the superinduced northerly 
 course, and was produced when the origiual features due to unequal 
 hardness of the metamorphic rocks reasserted themselves as the 
 overlying strata were removed. 
 
 To this cause may be attributed the remarkable deviation in 
 the course of the Fiddich at Coldhome, where the river bends 
 suddenly round and flows westwards to Dufftown, making an angle 
 of less than 60° with its track above the bend. 
 
 The ridge between Carron Hill and the Tips of Corsemaul now 
 forms the watershed between the Fiddich and the Isla, and rises 
 nearly 400 feet above the valley of the former stream. But at the 
 time when ridge and valley were alike concealed beneath the 
 covering of Old Eed Sandstone strata, the upper waters of the 
 Fiddich would naturally flow northward across the present water- 
 shed into the valley of the Isla. In the process of time the sand- 
 stones covering the ridge of metamorphic rocks were gradually 
 removed by denudation, and the stream, finding it easier to erode 
 the softer rocks that still filled up the Dufftown valley than to cut 
 through the ridge of schist and quartzite, turned to the west, thus 
 robbing the Isla of its headwaters and swelling the volume of a 
 smaller stream that must already have been cutting back out of the 
 head of the fault-determined valley below Dufftown. 
 
 A similar course of events seems to have determined the courses 
 of the river Lossie and the Black Burn in the north-west portion 
 of this area. 
 
 Prior to the removal of the general covering of sandstone from 
 this region the Lossie flowed seaward as a consequent stream, with 
 the same northerly trend that it still retains in the upper part of 
 its course above Dallas. It was joined by the Black Burn on the 
 west side of the Hill of Mulundy, and the combined streams, passing 
 northwards through the well-marked hollow through which now 
 runs the road to Eafford, fell into the river Findhorn somewhere 
 near the present site of Forres. As the sandstone covering was 
 gradually removed by the wasting process, the earlier topograpliical 
 features would again come into play ; and the Lossie, turned aside 
 by the ridge of metamorphic rocks that runs eastwards from the 
 Hill of Mulundy, eroded the softer strata that still occupied the 
 hollow and returned to the ancient river valley below Dallas. 
 The watershed between Eafford and Briach Mill is only about 
 twenty feet above the present level of the Black Burn at the latter 
 locality. It is thus probable that this stream retained its northerly 
 course to the Findhorn to a considerably later period. Finally 
 
however, the influence of the original surface features, coupled as 
 in the case of the Lossie with the cutting-back of a stream in the 
 valley to the east, produced the present deviation of the Black 
 Burn eastwards under the Eildon Hill. 
 
 The present channel of the Lower Spey, apart from the valley 
 through which it flows, is largely post-glacial. "Over the greater 
 part of its course through this sheet, and especially between 
 Ballindalloch and Carron, it is flowing over rock and still deepening 
 its bed, while the mass of fluvial and glacial deposits that still 
 remains in the principal and tributary valleys shows how deeply it 
 has trenched the waste-filled basin since glacial times. The swift- 
 ness of its lower course, which is abnormal in comparison with 
 the gradient of its middle section, is probably the effect of an 
 uplift along an axis that crosses the river considerably further up 
 the valley, and is of later date than the erosion of the higher 
 portions of its course. 
 
 The Spey may thus be regarded as a compound river, made up 
 of two sections of different age, and at unequal stages of erosion ; 
 while the portion which falls within the region under description 
 has been rejuvenated by uplift, and, like many other streams in the 
 area, affords an example of superinduced drainage. 
 
 A well-marked constriction of the Spey Valley occurs at 
 Aikenway Castle, 1^ miles N.KE. of Eothes. At this point the 
 quartzite of Ben Aigan at one time formed a rock-barrier which 
 dammed back the waters of the Spey over what is now the fertile 
 Haugh of Kothes, and was possibly high enough to divert 
 the course of the river north-westwards through the Glen of 
 Eothes. Indications of this former course of the Spey are found in 
 the high-level terraces that flank that glen, and can be traced 
 southwards into the river terraces between Eothes and Knockando 
 (see Chap. IX.). L. W. H. 
 
 Geological Structure in Relation to Population and Economics. 
 
 A close connection exists between the geological structure and 
 the distribution of the population of the country represented in this 
 map. This relation between structure and population only holds 
 good, however, for ground below 1000 feet above sea level, for at 
 higher elevations grain and green crops cannot be profitably 
 cultivated in this part of Scotland. Outside the burghs of Keith, 
 Dufftown, Eothes, and the villages of Aberlour, Newmill, Archies- 
 town, and Dallas, which are more or less engaged in small local 
 industries, the remaining portion of the sheet is either agricultural, 
 pastoral, or moorland. 
 
 The first factor which has determined the distribution of the 
 agricultural population appears to be the geographical position of 
 the various alluvial haughs, terraces, and fluvio-glacial gravels 
 which are distributed along the valleys of the Black Burn, the rivers 
 Lossie, Spey, Avon, Dullan Water, Fiddich, Isla, Deveron, and 
 their various tributaries. 
 
 It was on these terraces and lower valley slopes that the 
 
Geological Structure in Relation to Population and Economics. 7 
 
 agricultural population first settled in farms and crofts, while the 
 further extension of agriculture and population higher up the hill 
 slopes and across the areas which separated one valley from anothei 
 was chiefly determined by the nature of the intervening rock 
 zoneSi There is also an intimate connection between the size 
 of the farms and the extent of the alluvial deposits at any one 
 point. From Dandaleith to Dipple the river Spey has deposited 
 the largest haughs and terraces in this sheet, and on these are 
 situated the largest farms in the map. 
 
 The decomposition of the granulitic flagstones and schistose grits 
 produces a poor, damp soil, which is neither adapted for arable nor 
 pastoral purposes. These grits and flagstones are generally 
 covered by turf -peat and heather, while deep . peat mosses occupy 
 the hollows. We thus find that on the west side of the Spey and 
 on either side of the river Avon the ground over which this series 
 extends is chiefly utilised as grouse moors with a few scattered 
 grazings, while the population of this portion of the country is 
 almost entirely confined to the alluvial haughs and terraces which 
 intersect it. 
 
 The Middle Old Red Sandstone series, which extends from the 
 Gallows Hill to the river Lossie, is entirely composed of a coarse 
 conglomerate with a thin covering of gravelly soil. As this ground 
 is very suitable for the growing of timber, a large portion of this 
 area has been planted, and in consequence there is a very scattered 
 population. On the Teindland and around Thomshill the con- 
 glomerate is covered with a considerable thickness of sharp gravelly 
 drift. This deposit is largely derived from the denudation of the 
 Upper Old Eed and Triassic Sandstones of the " Laigh of Moray " 
 and was laid down over this part of the country by the Moray 
 Firth ice sheet. The whole of this area along with the small 
 portion of Upper Old Red Sandstone at Longmorn is well cultivated 
 and maintains a full agricultural population. 
 
 From the east side of the Spey to the margin of the sheet those 
 areas of the map which are occupied by the phyllites, black-schist, 
 and limestone, are generally well cultivated up to 1000 feet. 
 Surface drift derived from these rocks affords a clayey soil, the 
 lower part of which is generally a stiff till, and where this is mixed 
 with the peat in the valley bottoms a clayey loam is produced up 
 to 1000 feet. An agricultural population is pretty evenly 
 distributed in crofts and small to medium sized farms all over that 
 portion of the map occupied by these three members of the 
 Banffshire series, with the exception of that part which is included 
 within the Glen Fiddich deer forest. Above the limit of culti- 
 vation over these three zones the ground is either pastoral or else 
 planted with timber, with a very sparse population. 
 
 From Ben Aigan to the Black Hill of Corinacy many of the hill- 
 tops and ridges are occupied by the Banffshire quartzite, a hard 
 siliceous rock which does not readily produce soil. Many of these 
 hills carry no soil and are frequently covered with their own debris 
 overlaid with turf-peat and heather. When soil covers these 
 quartzite areas it is similar to that produced by the " Cromdale 
 
8 I!ayplanation of SJieet 85. 
 
 Hills series," and as it is poorly adapted for cultivation there is 
 almost no population where quartzite forms the rock of the 
 country. An exception to this absence of population over a 
 quartzite area is found at the foot of Glen Markie and around the 
 Eurn of Edinglassie. These two small valleys have a thick 
 covering of drift chiefly derived from the phyllites and black schists 
 which are in place to the W.S.W. of them. This is another instance 
 within the sheet where the character of the glacial deposits and 
 not the solid rock beneath has influenced the distribution of the 
 population. J. S. G. W. 
 
Pormations and Groups of Bock. 
 
 Old Red f-Uppe^' 
 
 Sandstone. 
 
 CHAPTER III. 
 
 Formations and Groups of Bock. 
 
 Aqueous. 
 
 Recent and ( Peat 
 Post-Tertiary. \ River and Lake Alluvium 
 Moraines. 
 Erratic Blocks. 
 Sands and Gravels. 
 Brick Clays. 
 Boulder Clay. 
 Striated Rock Surfaces. 
 Sandstones 
 
 SIGN ON MAPS. 
 
 Glacial Drift. < 
 
 Middle or 
 (^ Orcadian. 
 
 Conglomerate and Sandstones 
 Metamokphic. 
 
 Banffshire 
 Series. 
 
 Granulitic 
 
 Schists 
 of Central 
 Highlands. 
 
 Quartzite 
 
 Schistose Grit 
 
 Limestone 
 
 Dark Slates and Schists (" Black 
 Schist") 
 
 Clay Slates and Phyllites 
 
 Mica Schist 
 
 Granulitic quartzite, Quartzo- 
 micaceous Schists, and Flag- 
 stones 3£ in 
 
 Undifferentiated Schists and 
 
 m 
 
 
 I 
 9 
 
 Gneisses 
 
 Igneous. 
 
 Contemporaneous — Andesite of Old Red Sandstone Age 
 
 C Lamprophyre 
 Post- foliation. <[ Diorite 
 (^ Granite 
 
 Serpentine 
 Gabbro 
 
 Intrusive. 
 
 Pre-foliation. < 
 
 Epidiorite and Hornblende- 
 Schist 
 
 Foliated Granite or Augen- 
 Gneiss 
 
 Poc^ 
 Sm 
 D 
 G 
 
 U 
 
 BG 
 
 G? 
 
 In the published map the symbol c^ has been used for the Middle or Orcadian 
 Division. In the edition which will be subsequently issued c^ will be used. 
 
10 Explanation of Sheet 85. 
 
 General Geological Structure of the Area. 
 
 The ground east of the river Spey is chiefly occupied by the 
 rocks of the Banffshire series, the various members of which are 
 arranged in a succession of roughly parallel bands across the south- 
 eastern portion of the map between Glen Tervie, south of Ben 
 Einnes, and Keith. These quartzites, schists, and limestones 
 represent a portion of the belt of more or less altered sedimentary 
 rocks with associated igneous intrusions which extends almost 
 continuously across Scotland from the south-west of Argyllshire to 
 the Moray Firth. They are particularly well developed in the 
 adjoining sheet to the south (75), and have been described in the 
 explanation accompanying that sheet. 
 
 The granulitic schistose rocks of the Central Highland or 
 Moine schist type cover almost the entire western half of the 
 map. The more "siliceous portions of this group have been coloured 
 yellow on the map, but are distinguished from the quartzites of 
 the Banffshire series by the addition of the letter m to the index- 
 symbol X. 
 
 The quartz schists and flagstones form the western slopes of Ben 
 Einnes, the Cromdale Hills, and the high ground that rises to the 
 north-west of the Spey between Allt Arder and Delliefur; while 
 the wide moorlands that stretch northwards from the watershed to 
 the head waters of the Lossie are occupied by the undifferentiated 
 schists and gneisses of this series. The separation of the various 
 rock-types in this latter area is rendered difficult and indeed often 
 impossible by the great extent and thickness of the peat and drift 
 with which the hills are covered and the Consequent absence of rock 
 sections. For the same reason the line drawn on the map between 
 these rocks and the more siliceous group in the south, is a very 
 conjectural one. 
 
 A considerable area of conglomerate and sandstone occupies the 
 ground on either side of the Spey north of Rothes. These 
 sediments rest unconformably upon the schists, and are presumably 
 of Orcadian or Middle Old Eed Sandstone age. To the north of 
 the Glen of Eothes and along the margin of the map these are in 
 their turn covered unconformably by sandstones belonging to the 
 Upper Old Red Sandstone period, while smaller patches of these 
 latter rocks also occur at Dallas, Pluscarden, and Eafford. 
 
 The plutonic rocks are confined to the central and eastern 
 portions of the area under description, and the almost entire absence 
 of igneous masses in the Central Highland schists is a striking 
 feature of the western half of this sheet. The earlier intrusions 
 are represented by the basic and ultra-basic sills associated with the 
 Banffshire series and intruded into those rocks prior to the move- 
 ments that produced their present schistosity. To the same 
 period may be assigned the foliated granites or augen-gneiss that 
 pierce the schists in the neighbourhood of Keith. 
 
 Later than the schistosity is the large mass of unf oliated granite 
 which disrupts the rocks on both sides of the Spey at Aberlour, and 
 forms the mountain mass of Ben Rinnes and the Convals. A more 
 
General Geological Structure of the Area. 1 1 
 
 basic phase of this intrusion is probably represented by the diorite 
 of Hill of Stob and Netherly on the Burn of Eothes. 
 
 A few lamprophyre dykes are found in the quartz schists of 
 Ben Aigan, and a bed of contemporaneous porphyry or andesite 
 occurs in the Old Eed Sandstone of the Cabrach outlier, in the south- 
 east corner of the map. L. W. H. 
 
12 Eocplanation of Sheet 85. 
 
 CHAPTER IV. 
 
 Metamorphic RocTcs. 
 
 QUAETZITE. 
 
 On the east side of the river Spey the metamorphic rocks have 
 been thrown into a series of isocHnal folds which have determined 
 their arrangement over this area. It is more than probable 
 there is only one zone of quartzite ; the repetition of the rock in 
 parallel bands and detached lenticular masses, whose longer axes 
 lie north-east and south-west, being due to this system of folding. 
 As already indicated, the quartzite, owing to its greater hardness, 
 invariably forms the hills and ridges, while the lower slopes and 
 valleys are carved out of the softer phyllites, black schists, and 
 limestone. In this sheet there is no direct evidence that the 
 quartzite rests unconformably on the other members of the Banff- 
 shire series. The indirect evidence is very strong, for a glance at 
 the map shows that the main belt of quartzite which stretches from 
 the Glen Fiddich forest to Invermarkie is at various points in 
 contact with phyllite, black schist, and limestone. But it should 
 be borne in mind that, throughout the area included in Sheet 85, 
 the quartzite, phyllite, black schist, and limestone have been 
 affected by a common system of folds. In character the rock 
 varies from a very fine-grained homogeneous crystalline-granular 
 rock to a hard massive granulitic quartzite. In colour it 
 varies from grey white to a dirty yellow, and the finer-grained 
 varieties when freshly broken have a pinkish colour. The quartzite 
 hilltops of this portion of Banffshire are often covered with its 
 debris, which weathers with a snow-white colour. Over the greater 
 portion of the northern half of the area this rock is felspathic and 
 granulitised, and often passes into a quartzo-felspathic schist with 
 white mica developed along the divisional planes, while towards the 
 south-east the original clastic grains can still be recognised, and in 
 several localities bands of pebbly grit prove the sedimentary origin 
 of the rock. 
 
 In proceeding to describe the various areas of quartzite from 
 north-west to south-east, the first in order is that which extends 
 from near Craigellachie to the north of the Burn of Mulben and 
 forms the hills of Ben Aigan (1544 feet), and Knock More 
 (1167 feet). 
 
 The quartzite throughout this area is very uniform in character, 
 massive and granulitic, with the bedding planes well defined. 
 Numerous dips have been observed in the streams which flow down 
 the western slopes of Ben Aigan, and these indicate a general 
 
Metamorphic Bocks. 13 
 
 inclination to north-east and south-west. Tor about two miles 
 along the river Spey north and south of Boat of Bridge, a hard, 
 massive, purple quartzite is exposed. In the Burn of Mulben and 
 north to the boundary of the Old Eed Sandstone this rock is very 
 much shattered, and the subangular brecoiated portions have all 
 been re-cemented together by a siliceous base into a homogeneous 
 rock with occasional drusy cavities in which occur crystals of 
 quartz or barytes. The purple colour of the rock extends as far 
 south as the Woods of Knockmore, and is due to staining by Old 
 Red Sandstone. In the Burn of Mulben and within a short 
 distance of the eastern limit of this area bands of quartzite and 
 phyllite are folded together. 
 
 At Sheriffhaugh this rock loses its brecciated character, and the 
 Allt Daley which flows into the river Spey at this point affords an 
 almost continuous rock section to within a short distance of the top 
 of Ben Aigan. In the lower portion of this section thin bands of 
 quartzite inclined to E. 12 S. at angles varying from 10" — 15" 
 alternate with quartz schist and flagstones. Higher up, the dip 
 is inclined more to the south, the quartzite becomes more massive, 
 and the thicker and harder bands give rise to a series of cascades. 
 Towards the top of the hill the rock is occasionally brecciated, and 
 at the head of the section bands of quartzite are folded with the 
 mica-schist which occupies the ground to the east. 
 
 The tops of Knock More and Ben Aigan are covered with angular 
 debris of pink, grey, and yellow quartzite with very fine dendritic 
 markings, weathering white. On the banks of the river Spey at 
 Aikenway and below Arndilly House the rock is very much 
 shattered, and has been converted into a breccia with large and 
 small subangular fragments cemented together in a siliceous matrix 
 and stained purple by the recently removed Old Eed Sandstone 
 beds. The eastern boundary of this area is shown on the map by 
 a comparatively straight line, but this is due to the want of 
 exposures between the Glen of Mulben and Tanzie. At the latter 
 point a massive quartzite with black-schist above passes in below 
 the mica-schist to the east. The upper portion of the bimi 
 which flows past Arndilly House runs through a ravine with steep 
 cliffs of white and pink quartzite. 
 
 To the south of Rothes and on the east side of the wood of 
 Conerock there are several exposures of a very peculiar rock. It is 
 a brecciated-looking complex of vein quartz and quartzite in a 
 siliceous matrix stained irregularly in strings and patches with 
 htematite. The " Cone Rock," at one time the site of an ancient 
 fort, is situated in the wood half a mile to the west of Haughs, and 
 is entirely composed of this brecciated rock. It is probably a 
 fault breccia due to the line of dislocation described in Chapter II. 
 It contains numerous drusy cavities of all sizes lined with crystals 
 of quartz, and when cut and polished has a very beautiful 
 appearance. 
 
 Between Dufftown and Herricks Moss, north of Keith, small 
 isolated lenticular masses of quartzite occupy the tops of several 
 of the hills. A narrow belt of white quartzite extends along 
 
14 Explanation of Sheet 85. 
 
 the north-east bank of the river Fiddich on both sides of 
 Kininvie House, and in the branch burn at Hazelwood Cottage 
 vertical beds of the same rock are seen alternating with black- 
 schist and mica-schist. A considerable area of quartzite covers the 
 Scaut Hill and extends to the north-east as far as the Lochend 
 Wood. On the roadside opposite to Waulkmill the rock is much 
 shattered by the fault which follows the valley of the river 
 Fiddich between the Mains of Newton and Balvenie Castle. In a 
 small stream to the north-easb of Little TuUoch the highly inclined 
 beds are finely conglomeratic. The nature of the debris on the top 
 of this hill shows that the underlying rock is fine grained and in 
 places not much altered. 
 
 The flat moor between the Knockan and Machatties Cairn is 
 free from drift and covered by white quartzite debris and heather. 
 North of the " Cairn," in the small burn which passes down to 
 Broadrashes, bands of quartzite, black-schist, and phyllite, all 
 inclined at high angles, are seen folded together. A glance at the 
 map shows that in the north-eastern portion of this area the 
 quartzite is thrown into five sharp folds. In Tauchers Wood there 
 are several exposures of bands of pink quartzite with yellow spots, 
 inclined to the south-east at angles varying from 30° — 50°. 
 
 The rock which occupies the Moor of Auchanacie is a fine-grained 
 light-brown foliated quartzite with ill-defined patches of brown 
 staining. In many places it passes into a quartz-schist with white 
 mica developed along the planes of foliation. A similar rock forms 
 the small lenticular mass at Blackhill Wood to the south-west of 
 Keith. In the north-east corner of this sheet a wedge-shaped area 
 of quartzite stretches from Herricks Moss to within a short distance 
 of Newmill. In the stream section to the south of the moss the 
 rock is inclined to E. 25 S. at comparatively low angles and consists 
 of hard, laminated, flaggy quartzite. The extension of this band to 
 the south-west has been traced by means of numerous shallow 
 quarries and rook knobs. The western slope of the Cairds Wood 
 Hill south of Keith is occupied by a lenticular area of very hard 
 massive quartzite traversed by numerous veins of quartz. At 
 Drummuir Station the ground between the public road and the 
 railway is covered by an oval shaped area of very hard yellowish 
 quartzite surrounded by a belt of black-schist. At the back of the 
 station this schist is seen passing in below the quartzite with a 
 south-easterly dip. 
 
 South of Dufftown the ridge of high ground which separates the 
 ^valleys of the DuUan Water and river Fiddich is also formed 
 of quartzite. To the south-west of Pitglassie it is brecciated and 
 granulitic, while" crags of white quartzite rise to the south of Cairn- 
 more. Between Carron and Bellyhack Hills, in the Parish of 
 Botriphnie, no rock is seen in place, but the surface is thickly 
 covered with angular quartzite debris. 
 
 The largest band of quartzite enters this sheet in the Glen Fiddich 
 Forest to the south of the Hill of Glenroads and traverses the map 
 in a north-easterly direction. This is the northern extension of the 
 area which lies on the west side of Glen Suie* in the sheet to the 
 
 * Explanation of Sheet 75, p. 9. 
 
Metmnorphic Bocks. 15 
 
 south (75). Its outline is very irregular, and its breadth varies 
 from 400 yards up to 3 miles. From the southern boundary of 
 the map to Glen Fiddich lodge very little rock is seen in place, but 
 its position is inferred from the quantity of quartzite debris which 
 covers the hilltops. A glance at the map shows the folding of 
 the quartzite in Glen Fiddich between Tor Elick and the Hill 
 of Clais nan Earb, with the result that the same beds of phyllites 
 and limestone are repeated on both sides of these two hills. From 
 the lodge to below Smithstown, the river Fiddich exposes a good 
 section consisting of grey, flaggy, massive quartzite with mica- 
 schist partings inclined to the south-east at various angles. To 
 the north-east of Laird's Seat grey phyllites pass in below this 
 rock, and at Laggan, where the boundary line crosses the riyer, a 
 cliff of soft decomposing quartzite is in close proximity to the 
 black-schists. To the north of the Scalp Hill this belt of 
 quartzite is thrown into a series of folds, and its boundary then 
 turns to the south as far as Garbet Hill at the head of Glen 
 Markie. 
 
 That the beds of quartzite are often repeated by folding to the 
 east of Glen Fiddich is evident from the fact that between Cairn 
 Crome and Ben Main there are three small areas of phyllite and 
 limestone entirely surrounded by quartzite. Between the Meikle 
 Balloch Hill and Burntreble the strike of the beds changes from 
 its normal direction to north and south, and at the same time the 
 vertical bands of quartzite are thrown into a series of folds. The 
 result of this plication is to carry the boimdary of the quartzite 
 from Ballochford to a poiat near Burntreble farmhouse, whence it 
 has been traced north-eastwards as far as the HUl of Dumeath, a 
 distance of four miles. 
 
 The road from Dufftown to the Cabrach passes to the south of 
 the Meikle Balloch Hill through the " Glack," and at this point the 
 white quartzite is converted for some distance into a fault breccia 
 composed of sharp angular fragments of quartzite of various dimen- 
 sions embedded in a siliceous-felspathic matrix. 
 
 The angular debris and occasional exposures of rock seen on the 
 high ground to the east of Glenmarkie indicate that the ridge that 
 extends northwards from Garbet Hill to Gallow Hill, and the upper 
 part of the eastern slopes of the glen, are occupied by quartzite, but 
 the position of the boundary line between this rock and the black 
 schist is obscured by the almost uniform covering of peat and 
 heather. Thick-bedded quartzites first appear in the stream section 
 below Burnside of Markie, where they dip E. 28 N. at 50°, and from 
 this point to the Mill of Invermarkie bands of quartzite alternate 
 with black schist and thin sills of foliated diorite. To the north of 
 this section the bands of quartzite become vertical, and this rock 
 covers the whole of the Tips of Corsemaul as far as Bodylair and 
 " the Crofts." Between these two localities and the hill of Dumeath 
 this zone of quartzite divides into two separate belts. Both of these 
 pass iato sheet 86, the northern one at Blacking, and the other at 
 the Wood of Straitinnan. On the east side of Glen Fiddich the 
 Scant Hill is covered with a very fine-grained crystalline granulitic 
 
16 Explanation of Sheet 85. 
 
 yellowish quartzite. A local base to the quartzite is indicated 
 by the coarse pebbly grit, almost a conglomerate, that occurs on 
 the ridge of the Black Hill in the south-east corner of the map. 
 The rock is not actually seen in place, but the large angular masses 
 which protrude in profusion through the peat that covers the hill top 
 indicate its presence below. The well rounded pebbles are some- 
 times as much as 4 or 5 inches in diameter and are chieily composed 
 of white quartzite, suggesting that this rock is due to local erosion. 
 Its local character is also shown by the fact that less than a mile 
 to the east 'it passes along the strike into quartz-schist. To the 
 north of this hill a narrow and much folded belt of grey and white 
 quartzite forms the division between the black schist and phyllites. 
 The small lenticular band which stretches from Bridgend in the 
 valley of Burn Treble, west of the Deveron, to the Kelman Hill is 
 a grey foliated schistose grit. It lies on the same line of strike and 
 is evidently an infold of the Blackwater beds. Below the Mill of 
 Lyneburn on the Deveron thin bands of a similar schistose grit are 
 found associated with the black schist. J. S. G. W. 
 
 Limestone. 
 
 The main outcrop of limestone in the area east of the Spey 
 extends in a narrow and almost continuous belt from the head of 
 Grien Tervie through Glen Einnes and along the DuUan Water to 
 Dufftown ; and thence by Loch Park and the valley of the Isla to 
 Keith. On both sides of this belt there are numerous small isolated 
 bands and small lenticular areas of limestone which are associated 
 either with the black schists or with the phyllites. The main out- 
 crop varies considerably in breadth, this variation being partly due 
 to the conditions under which the limestone was originally deposited, 
 and partly to the intense overfolding to which it has subsequently 
 been subjected. A description of the Banffshire limestone is given 
 in the explanation to sheet 75, in which it is pointed out how a 
 small band, originally of no great thickness, may through repetition 
 by folding be made to occupy a very large extent of ground. 
 
 The limestones which are wrought or burnt for lime throughout 
 this district are very uniform in character; they are highly 
 crystalline, and vary from light to blue grey in colour. They often 
 show distinct bedding-planes and bands of light and dark grey 
 schist. In some localities this rock has been brecciated and 
 re-cemented together by calcite, while in other places the bedded 
 limestone is traversed by large veins and eyes of pink calcite. The 
 less pure bands are generally dark, much thinner, weather with a 
 rusty brown colour, and are often associated with black schists. No 
 contact minerals have been observed in the main outcrop of this 
 rock where it is in close proximity to the Ben Einnes granite, but 
 their absence may be due to the comparative purity of the limestone. 
 
 At the head of Glen Einnes, below Nether Auchmore, several 
 strong springs locally known as the " Lagantoul "Wells " flow from 
 the limestone. In a neighbouring quarry the rock is a grey saccha- 
 roidal bedded limestone traversed by veins of calcite. Prom this 
 
Metamorphic Eochs. 17 
 
 point northwards the belt has been traced chiefly by small quarry 
 openings, but at Succoth there are several good exposures in the 
 DuUan Water. In all these the beds dip to the south-east. Below 
 AUamichie a white and blue crystalline limestone shows colour- 
 banding. At Nether Cluny this belt crosses from the right to the 
 left side of the Dullan Water, where a solid blue and white limestone 
 appears which has been quarried and burnt for lime. Along the 
 bed of this stream the limestone has been worn into numerous pot- 
 holes. Within a short distance, at the wood above Pittyvaich, the 
 rock passes into a contorted limestone with thin calcareous and 
 black-schist partings. The local crumpling seen at this point is 
 the first indication of the numerous large folds into which this zone 
 has been thrown in the neighbourhood of Dufitown, about a mile to 
 the north-east. To the west of the Glack of Pitglassie, in the 
 Dullan section, there are several infolds of the limestone, in which 
 the rocks are much contorted, and exhibit signs of considerable 
 movement. To the west of the point where the Dullan Water turns 
 sharply to the north, and where a spur of the limestone projects 
 into the stream, there are numerous very fine potholes, two of 
 which may be seen on the face of the cUff, one above the other, 
 marking different levels of the water as the stream cut down through 
 the limestone. The upper one is locally known as the "Griant's 
 Chair," and the lower as " Giant's Footstool." On both sides of the 
 Dullan Water, at its junction with the river Fiddich, quarries in this 
 band have been wrought for a long time and the stone burnt for 
 lime. In the south or Eichmond Quarry, a blue limestone, in thin 
 beds with partings, dips below the black schist ; while in the north 
 or Tininver Quarry the rock is a solid blue crystalline limestone. 
 Proceeding down the Fiddich section this rock for some distance is 
 very much slickensided, contorted and folded. This is succeeded 
 for about 200 yards by black schist in a similar condition, the result 
 of the folding to which this belt to the east of Dufftown has been" 
 subjected. Immediately above the railway bridge the limestone is 
 in a shattered and plicated condition; and on the opposite side of 
 the river at Parkbeg a large lime quarry has been opened and 
 wrought successfully for many years. Here the beds also show 
 signs of considerable movement, are much slickensided, thrust over 
 one another, and veined with calcite. A good exposure of this 
 zone is afforded by the railway cutting along the side of Loch Park. 
 Here the limestone is considerably shattered and folded, and where 
 dip can be observed it is usually at a high angle. Intercalated 
 with the limestone are black schists and thin calcareous bands with 
 veins of white and pink calcite. A portion of the limestone is 
 repeated between the foot of Loch Park and Drummuir Castle by 
 several folds, which " nose-out" to the north-east of the castle ; 
 while at the same time the main outcrop sharply folds on itself at 
 Midthird and then continues on to Drummuir Station. At this 
 point the limestone is thrown into a compound fold and can be 
 traced round both sides of the small quartzite area west of Forkins. 
 In the small den west of Lower Towie there is a small infold of 
 grey crystalline limestone with black schists, both showing con- 
 
 B 
 
18 Explanation of Sheet 85. 
 
 siderable plication. Here were situated the Drummuir Limeworks, 
 but the quarry was abandoned about six years ago when the lime- 
 stone to the north became exhausted. 
 
 At Poolside the beds which form the edge of this zone are the 
 only ones exposed, and consist of calcareous schists dipping below 
 black-schists. Limestone appears at Millcrof t, and in the burn to the 
 north of Coldhome an outcrop indicates the position of this zone as far 
 as the limework at Braehead. This quarry has been opened in a grey 
 crystalline limestone with thick partings of black-schist. A short 
 distance to the south of it there are two infolds of dark limestone 
 and calcareous schist. Almost at the point where this zone passes 
 out of the sheet at the 500-feet contour line, there is a small opening 
 in a bed of blue crystalline limestone dipping to the south-east. 
 Another small infold of a similar rock occupies the bottom of the 
 valley of the river Isla from near Blackhill Wood to the east of 
 Fife-Keith. At the former point are situated the Maisley, and on 
 the opposite bank of the river the Douglasbrae Limeworks, both 
 of which are now abandoned. In each of the quarries attached to 
 these works light grey crystalline limestone veined with calcite 
 dips to the south-east. This is in turn overlaid by black-schist, 
 and a similar section is exposed in the railway cutting east of Pife- 
 Keith. 
 
 Isolated areas of limestone due to small infolds with the black- 
 schist are found on both sides of the main outcrop. One of these 
 occurs two miles to the west of Fife-Keith and close to the Mulben 
 road, where there is a good exposure of a grey crystalline bedded 
 limestone about twenty feet thick. This band is also seen crossing 
 the Eosarie Burn. Another isolated band enters the sheet to the 
 south of Keith and is quarried at the Blackhillock Limeworks. 
 The workable rock is about 40 feet thick, and the beds are nearly 
 horizontal. The grey limestone at Auchindown Castle in Glen 
 Fiddich forms a craggy slope about 250 feet high, and a similar 
 rock occurs on the same line of strike near Earnfold, where it is 
 very much brecciated with small veins of haematite. The band 
 which crops out in G-lenmarkie below Belnaboyle is highly contorted 
 and folded. It is a poor grey-white sandy limestone, but in prox- 
 imity to the diorite it becomes much purer, and is almost converted 
 into marble. A small band enters the map in the Glen Fiddich 
 forest, while the small lenticular areas on both sides of the Hill of 
 Clais nan Earb are doubtless isolated infolds of the same. 
 
 J. S. G. W. 
 
 Black-Schist. 
 
 The largest area of black-schist in this map lies between 
 Dufftown and Keith, and extends westwards to the centre of the 
 Parish of Boharm. The general character of these rocks is that of 
 a dark carbonaceous schist with some slate bands. The amount of 
 carbonaceous material present in the rock constantly varies ; it is 
 generally more abundant in the region mentioned above, less so in 
 the central area and increases again in the belt to the south-east. 
 
Metamorphic Bocks. 19 
 
 Its rate of decrease is also very irregular, a very dark blue schist 
 passing in a very short distance along the line of strike into a 
 phyllite or mica-schist by the disappearance of the carbonaceous 
 material. 
 
 Where these schists have a blue-black colour they are often 
 distinctly graphitic. In many instances the original bedding 
 planes can be recognised, especially in the less metamorphosed 
 slates, but these are often obliterated by the subsequent foliation 
 and the strain-slip-cleavage which has produced the corrugated 
 structure so prominent a feature in the more schistose varieties. 
 Garnets are tolerably abundant in these schists in certain localities, 
 and there is also a sporadic development of secondary minerals such 
 as actinolite, kyanite, andalusite, and staurolite. The more frequent 
 occurrence of these accessory minerals in the neighbourhood of the 
 Ben Einnes granite, and the gabbros and diorites of the Blackwater 
 and river Deveron, suggests their thermo-metamorphic origin. One of 
 the best sections in this district is that afforded by the burn and 
 its tributaries which joins the Fiddich at Mains of Newton, about 
 a mile and a half to the east of Craigellachie. From the foot of 
 this burn to the Mulben road the section displayed is entirely 
 composed of soft, twisted, and corrugated coal-black schists with 
 thin bands of limestone. These beds are strongly graphitic, and in 
 two of the small streams above the bridge they contain a con- 
 siderable quantity of iron pyrites, whUe several bands show finely 
 developed crystals of actinolite up to four inches in length. At the 
 foot of the small burn below Dinnyhorn black-schists with thin 
 bands of limestone dipping north-east and south-east are succeeded 
 by phyllites with strains and partings of black-schist and thin 
 limestones. The rapid interfolding of the beds in this section 
 results in the frequent repetition of the same bands. In the 
 section at Knockan and in the two small burns immediately to 
 the north similar folding is seen, and between the quartzite of 
 Machatties Cairn and the phyllites of Mulben a comparatively thin 
 portion of this zone is in this way made to occupy a considerable 
 area. As these schists east of Auchlunkart House approach the 
 foliated granite of Mulderie Hill they become garnetiferous, and 
 alternate with bands of mica-schist. A very good section of these 
 schists, with minute puckering and folding along the foliation planes, 
 is displayed in the burn to the west of Cabbachs. From the line 
 of fault north of Craigellachie north to Auchlunkart the western 
 boundary of this zone is well defined, and in many of the small 
 streams intersected by this divisional line the phyllites are seen 
 dipping in below the black-schists. 
 
 The small burn that joins the river Fiddich immediately to the 
 north of the Farm of TuUoch flows over dark schists full of iron 
 pyrites, and the decomposition of this mineral gives rise to a thin 
 efflorescent coating of alum on the rocky sides of the ravine, while 
 the water which trickles over the rocks is strongly impregnated 
 with the same salt. South of Balvenie Castle, on the left bank of 
 the river Fiddich, there is a very fine section showing vertical and 
 highly inclined bands of black-schist, which at the upper end of this 
 
20 Eocplanation of Sheet 85. 
 
 rock exposure are interfolded with the Dufftown limestone. In the 
 stream below Auchanhandock, south-east of Dufftown, and also at 
 its foot, bands of black-schist are found in contact with phyUites, 
 but from the latter point to near Drummuir the line between this 
 zone and the mica-schists is rather indefinite on account of the 
 absence of rock exposures. 
 
 In the Drummuir Castle burn and also in that at Tenatown, 
 black-schists with some thin quartzose bands are folded with thin 
 beds of blue crystalline limestone. The triangular area around 
 Starhead, north-east of Drummuir Station, affords numerous 
 exposures of this schist, and in the small stream which joins the 
 Burn of Davidston to the east of Howdoup the beds are very dark, 
 carbonaceous, and finely corrugated. The alluvial flat which extends 
 eastwards from Mulben to Newmill forms the northern boundary of 
 this zone to within a mile from Fife-Keith. At this point the 
 boundary line folds back upon itself for some distance and thence 
 continues with a north-east course towards Keith. Close to this town, 
 at the old limestone quarry of Braehead, this schist is very much 
 twisted, and at Blacldiillock and around the Cairds Wood it is very 
 dark and often contains much graphite. At the southern margin 
 of the map similar rocks occupy the col between the Tervie and 
 Favat burns and extend northwards into Glen Einnes as far as 
 Succoth. In the burn of Bahnerion they are very black, with 
 intercalated bands of limestone. J. S. Gr. W. 
 
 Corrugated black-schists, more or less graphitic, are well exposed 
 along the bum of Tervie, whose course between Tomachlaven and 
 Mains of Morinsh is parallel to the strike of the rocks. With them 
 are intercalated numerous thin calcareous bands, and from Lagavaich 
 a broad band of pure and highly crystallised blue-grey limestone, 
 intensely folded and contorted, follows the course of the stream to 
 the edge of the sheet. The exposures seen near the head of the 
 Tervie Burn and in the small stream immediately south of Black- 
 knowe, show that as these schists approach the southern boundary 
 of the Glen Einnes granite they become garnetiferous and also 
 develop large and perfect crystals of stauroHte and andalusite. The 
 relation of these crystals to the puckering of the schist proves that 
 they were formed subsequently to the movements which produced 
 the puckering or aiisweichmigsclivage. L. W. H. 
 
 The central black-schist area extends in a north-east direction 
 from near Auchindown Castle to Corsemaul and crosses the Hill of 
 Mackalea into Glen Markie; the extremely irregular course 
 represented by its outcrop being due to the rapid folding of the 
 beds. Auchindown Castle stands upon a cliff formed of vertical 
 beds of blue crystalline limestone, and in the ravine below, on both 
 sides of this crag, bands of black-schist are seen dipping towards the 
 limestone. The schists here and also at a point 600 yards lower 
 down the Fiddich are spotted and contain small knots. The hill 
 burn which joins the river Fiddich below the castle, gives a 
 continuous rock exposure in which the beds have a general inclin- 
 ation to the south-east, the upper portion of the section being 
 composed of slaty bands which are seen to pass below the yellow 
 
Metamorphic Boohs. 21 
 
 quartzite that caps the top of the hill. Due west from the cairn on 
 the Scalp Hill and about three hundred yards below the edge of the 
 quartzite a considerable quarry has been opened in one of -the slate 
 bands. These slates show original bedding planes, are very badly 
 cleaved, and partake more of the nature of a flagstone. This quarry 
 is now abandoned. On the north-west shoulder of the Hill of 
 Mackalea the same band has been recently opened out, but the 
 quality of the slate is very indifferent. At Corsemaul, Eaehutcheon, 
 and Earnfold, thin lenticular bands of dark grey limestone are 
 associated with these schists. In Glen Markie this black-schist, 
 together with the dark impure limestone, is traversed by numerous 
 sills of basic rock which have produced a certain amount of contact 
 alteration in the schist. 
 
 At the head of the Corryhabbie Burn there is a considerable area 
 of very dark black-schist with slate bands. The beds are inclined 
 to the south-east and pass below the quartzite which lies between 
 this glen and Glen Fiddich. At the Folds of Corryhabbie and along 
 their line of strike, these beds are interfolded with and pass into 
 grey flaggy phyllites. A small lenticular belt of grey and black 
 slates with crumpled graphitic bands extends along the east side of 
 Glen Piddich and passes into the sheet to the south. Another band 
 of black-schist crosses the south-east corner of the sheet from 
 Ardwell to Succothbeg in the valley of the Deveron. At Lower 
 Ardwell in the river section and alongside the turnpike road there 
 are exposures of slates with knots and crystals of andalusite. This 
 band crosses to the east side of the river Deveron, and towards the 
 top of the Hillock of Echt burn very hard black-schists are seen 
 passing into grey knotted and andalusite schists. In the streams 
 around Succothbeg and Meikle-Gouls the schists are vertical, very 
 black, and contain a considerable quantity of graphite. Below 
 Beldornie Castle the river has cut a deep gorge through crumpled 
 and contorted black-schists which show a considerable amount of 
 contact-metamorphism, doubtless due to the proximity of the 
 epidiorite of Wallakirk. ' J. S. G. W. 
 
 Mica-Schists, Clay-Slates, and Phyllites. 
 
 The mica-schists, clay-slates, and phyllites on the east side of the 
 river Spey form a distinct series by themselves. These different 
 members pass so gradually from the one into the other that it has 
 been found impossible to separate them on the ground, the mapping 
 being rendered still more difficult in Lower Banffshire by the thick 
 covering of drift. 
 
 The phyllites are best developed in the area which lies between 
 Keith and the Old Eed Sandstone region to the south-east of Foch- 
 abers. The most typical section is found in the railway cutting below 
 Craighead to the west of Mulben Station, where the beds dip to 
 E. 25 S. at an average angle of 30". These schists vary in colour from 
 light to dark grey, and are all very fine in texture ; the bedding 
 planes are well defined, and their surfaces show minute puckering of 
 the lamellae. At several points in this section the phyllites contain 
 
22 Uxplanation of Sheet 8S. 
 
 strains of black-schist, and also thin calcareous bands up to ^-inch 
 in thickness. These latter are very siliceous, and in some instances 
 approach the condition of a calc-silicate. At the east end of the 
 section the schists alternate with a few bands of thin siliceous 
 rock. 
 
 Phyllites also occupy the wedge-shaped area which extends south 
 to near Craigellachie, and are generally inclined to the south-east. 
 At Cummingston, and 1000 yards to the south-west of the Church 
 of Boharna, good bands of clay-slate are associated with them. In 
 the burn which flows from Gow Moss to Mills of Mulben the 
 phyllites have black-schist partings and thin white calcareous bands, 
 and similar calcareous beds are intercalated with purple phyllites 
 at the foot of the burn of JForgie and below Newton. Midway 
 between these two localities we find green unctuous schists with 
 yellow streaks, while towards the head of this burn the phyllites 
 become very fissile, the laminse in some cases being no thicker than 
 a sheet of paper. Thick, flaggy bands of clay-slate with schist 
 partings are exposed in the burn to the east of Tarrymount, and in 
 the vicinity of Foggie Moss some good bands of purple and green 
 clay-slates have been quarried for roofing slate. 
 
 In the stream to the west of Newmill, north of Keith, knotted 
 mica-schists overlie fine grey flaggy schists with very fine wavy 
 crumpling on their bedding planes. In the river and railway 
 section near the old railway station of Keith, phyllite and clay 
 slate bands alternate ; and along the same line of strike to the west 
 of Fife-Keith these pass into strong grey mica-schists. 
 
 A well-marked belt of this schistose series stretches from a point 
 near the head of Glen Einnes to the eastern edge of the sheet at 
 the Hill of Shenwall. From Oorryhabbie to the Coulalt Wood the 
 phyllites are very uniform in character ; grey in colour, often thick 
 bedded and flaggy, with a general dip to the east and south-east at 
 varying angles. In the Dullan Water between Hardhaugh and 
 Nether Cluny the section displays bands of grey mica-schiet and 
 calcareous phyllites with occasional bands of black-schist intimately 
 twisted and interfolded. There is also a good exposure of this 
 series in the river Fiddich below TuUochallum, and at its western 
 extremity phyllites and black-schists are seen folded together. 
 This is succeeded to the east by grey and flaggy phyllites with 
 calcareous schists, some of the latter being so far altered by 
 metamorphic action as to have been converted into calc-silicate- 
 hornfels of which the principal component is tremolite (see Chap. 
 VII.). 
 
 From the river Fiddich to the burn of Davidston the phyllites 
 become flaggy, and are intercalated with bands of mica-schist. On 
 the north side of the Hill of Bellyhack there are numerous rock 
 exposures of crumpled flaggy garnetiferous mica-schist. In the 
 deep ravine which lies to the south of the Mains of Pitlurg the rock 
 slopes are composed of hard slaty green phyllites with calcareous 
 bands and partings of mica-schist that have a general inclination to 
 E". 10 W. The face of the quarry at the west end of this ravine is 
 composed of grey and green flaggy phyllites with soft limy partings.- 
 
Metamorphic Bocks. 23 
 
 The thick phyllites retain their original bedding, while the 
 calcareous partings show a distinct foliation at an oblique angle to 
 their orignal planes of deposition. Thick-bedded garnetiferous 
 mica-schists with partings of soft mica-schists containing actinolite 
 occur at Mains of Davidston. 
 
 The zone of phyllitRs and naiea-schists which enters this sheet in 
 the Glen Fiddich Forest is very much folded, the beds being either 
 vertical or inclined to south-east at high angles. On the hill to the 
 south-west of the lodge a roofing-slate quarry has formerly been 
 wrought in a dark clay-slate band. In the Burn Treble section the 
 beds of grey phylHte are often vertical and contain thin bands of 
 black-schist. J. S. G. W. 
 
 The rapid alternation of the different zones of this Banffshire 
 series and the basic igneous rocks associated with them, produced 
 by isoclinal folding at high angles, is well illustrated in the 
 continuous rock section exposed along the Blackwater for nearly 
 two miles above its jimction with the Deveron. 
 
 Ascending the Blackwater from the bridge we find grey 
 phyllites alternating with dark slaty schists containing' incipient 
 knots, and also several thin sills of basic rock, the whole arranged 
 vertically, or inclined to the east at high angles. These are 
 succeeded rather more than half-a-mile above the bridge by a 
 lenticular infold of grey gritty quartzite or schistose grit, which 
 is in contact on its eastern side with a basic sill containing 
 calcite. This rock proves on microscopic examination to have 
 lost none of its clastic character {see Chap. VII.). Bands of this 
 grey grit appear along successive isoclinal folds and are repeated 
 five times between this point and the alluvial flat beneath the 
 ruined buildings a mile higher up the stream. The portions 
 of the section between the grit outcrops are occupied by alterna- 
 tions of phyllite, black slate, knotted and andalusite schist, with 
 several gabbro sills. L. W. H. 
 
 In the south-east corner of the sheet, and to the north-east of 
 the Craigwater Hill, the phyllites and black-schists are often 
 knotted, and also contain scattered crystals of andalusite. 
 
 J. S. G. W 
 
24 Uxplanaiion of Sheet 85. 
 
 CHAPTEE V. 
 
 Metamorphic Bocks — continued. 
 Granulitic Schists of the Central Highlands 
 
 The assemblage of rocks which occupy the ground on either side 
 of the Spey and Avon in the south-west portion of the map are 
 those which have been described in the explanation of the sheet to 
 the south (75) under the name of the Cromdale Hills Series. As 
 this series is now regarded as part of the wide-spread group of 
 Central Highland rocks of Moine Schist type, it has been thought 
 advisable to discard this purely local designation. 
 
 They may be described as a siliceous series in which quartz is 
 generally the chief constituent, but variable in character between 
 quartzites, mica-schists, and gneissose flagstones, according to the 
 relative amount and disposition of the felspar and micas present in 
 them. 
 
 Though the original clastic structure in these rocks has been 
 obliterated by subsequent movement, and they are now holo- 
 crystalline and completely granulitic in character, the planes of 
 original bedding are still often recognisable in the form of colour 
 bands and dark laminae. In the flagstones of the burn of the Cowlatt, 
 near Knockando, north-west of the Spey, planes of false or current 
 bedding are clearly indicated by lines oblique to the bedding 
 planes. These dark laminae when examined under the microscope 
 are found to be composed of heavy residual minerals such as 
 ilmenite, rutile, and zircon, thus offering a conclusive proof of the 
 sedimentary origin of the rocks in which they occur. 
 
 The constant variation in the nature of these rocks is to a 
 considerable degree no doubt due to original differences in sedi- 
 mentation, but may also be attributed to the effects of subsequent 
 mechanical movement. The area is one of intense plication, in 
 which the rocks have been thrown into a series of complex flattened 
 isocUnal folds, along the different limbs of which the differential 
 movement and consequent deformation varies in amount. So rapid 
 is the repetition of these folds, that where their crests are not 
 visible, or have been removed by denudation, the appearance 
 produced is that of regular parallel bedding with a general 
 inclination to the east. 
 
 The double-shafted arrows used in this portion of the map do 
 not however represent the dip of the original planes of deposition, 
 but indicate the inclination of the foliation planes, which may, and 
 indeed often do, coincide at any point along the limbs of the folds 
 with the bedding planes. 
 
Metamorphic Bocks. 26 
 
 The varying character of the rocks as affected by this intense 
 plication, is admirably displayed in the deep ravines at the head of 
 the Tormore Burn on the west side of Cragganmore, near Ballin- 
 dalloch. The arches of the minor folds are occupied by lenticular 
 cores of comparatively unmoved quartzite, which passes along 
 either attenuated limb of the fold into a fissUe quartzo-felspathic 
 schist, in which white mica has been plentifully developed under the 
 increased shearing strain. The result of this process, continued 
 throughout the different portions of a set of compressed overfolds, 
 will obviously be the production of a series of rapidly alternating 
 bands of quartzite and quartz-mica-schist, such as we find here and 
 in several other of the stream-sections of the Cromdale Hills.* 
 A quarry in the wood on the north-west side of Cragganmore, 
 1| miles south of Ballindalloch Station, also gives a good section of 
 the overfolded and sheared quartzites, associated with rocks of the 
 gneissose flagstone series containing two micas and much felspar. 
 
 The main outcrop of the gneissose flagstones is found along the 
 valley of the Avon and crosses the lower part of Glenlivet. The 
 rocks are visible at many points along the stream between 
 Drumin and Mill of Tommore. The apparent dip of the beds is 
 generally at a high angle and at the mouth of the Livet Water 
 nearly vertical. The inclination is towards the east except near 
 Craggan, where one of the few instances of a reversed westerly 
 dip occurs. These flaggy beds are also well seen in the Livet Water, 
 one mile above Drumin, where they are exposed on either side of 
 the stream between the old and new bridges, and are inclined to 
 south-east at angles of 15° — 40°. 
 
 The quartzose members of the group appear again on the eastern 
 side of Strathavon, and form the hills above Morinsh and the south- 
 west slopes of Ben Einnes. Much of this ground is covered with 
 peat and drift, and rock exposures are not abundant. The scars 
 and rocky gullies on the north face of Cairnacay are formed of a 
 tolerably massive and very crystalline yellowish quartzite which 
 weathers with a white crust. This rock is somewhat similar in 
 outward appearance to the quartzite of the Banffshire series, but a 
 closer examination reveals the presence of black mica disseminated 
 in minute flakes through the rock, while where the quartzite is more 
 sheared white mica is developed along the planes of movement. 
 On the HUl of Deskie, the slopes of Corshellach, and Cairn 
 Mulgainich the shearing is more pronounced and the rock much 
 more schistose ; while striping, produced by the drawing out of the 
 mineral particles in one determinate direction, is often well 
 seen, the direction of movement being to the north-west. 
 
 On the west side of the Cromdale Eange the mica-schists are 
 more predominant, but owing to the amount of drift that covers the 
 hillsides it is not often possible to separate them from the more 
 siliceous members of the series. The approximate boundaries of 
 one of the larger belts of mica-schist are shown on the map along 
 the western slopes of Creag an Tarmachain, and the rock is exposed 
 in a fairly continuous section in the Btim of Coire Seileach and its 
 
 * See Explanation of Sheet 75, p. 18. 
 
26 Uxplanation of Sheet 86. 
 
 tributaries. The flaggy quartzites and quartz-schists that are seen at 
 intervals along the course of the main stream above the bridge at 
 Advie Mains, are succeeded two miles south of the bridge by a fine- 
 grained fissile mica-schist, containing small garnets, and aggregations 
 of mica in the form of incipient knots. The schist is puckered and 
 cleaved, and the cleavage planes are oblique to the planes of 
 foliation. A good section of these schists is also given by the first 
 tributary burn on the right (Burn of Garvault on the six-inch map)-. 
 The apparent dip is south of east at somewhat low angles, and near 
 the head of the stream the schists are succeeded by sheared 
 quartzite with almost horizontal folding. 
 
 Crossing the river Spey we find the extreme south-west margin 
 of the map occupied by a grey muscovite-biotite-gneiss, fine-grained, 
 and thoroughly granulitic. The rock is only visible in a few places 
 on the hill slopes two miles north of Auchnagallin, but is extensively 
 displayed just beyond the western limit of the sheet, in the Cree 
 Dearg and on Carnghille Chearr, where it is in a high state of 
 crystallization and filled with veins of reddish biotite-granite. 
 
 The somewhat conjectural boundary-line drawn northwards along 
 the drift-covered slopes of Cam an Loin and Cam Euigh an Uain, 
 separates these gneisses from the siliceous rocks of Moine Schist 
 type which cover a wide area to the north and east, extending over 
 the high moorlands which lie between the Spey and the head waters 
 of the Lossie. A large part of this area is uniformly covered with 
 hill-peat and thick drift, and it is only where the hill streams have 
 cut deeply through these superficial deposits that the rocks are laid 
 bare. The prevailing type of rock in this region is a more or less 
 felspathic quartzite or quartz-schist, in which biotite, disseminated 
 through the rock in minute specks or flakes, is a constant though 
 not abundant constituent. The amount of shearing and interstitial 
 movement constantly varies, and the rock passes rapidly from a 
 comparatively unmoved and massive quartzite into a thoroughly 
 schistose rock in which white mica is abundantly developed along 
 the planes of movement. 
 
 The Burn of Tulohan and its tributaries afford perhaps the most 
 continuous section of these rocks. In the deep ravines cut by the 
 head waters of the stream the granulitic quartzite shows signs of 
 much deformation and has been rendered thoroughly schistose. 
 These schistose quartzites contain pink felspar and abundant white 
 mica. The burn of the Black Loch runs for some distance along a 
 line of fault, in the neighbourhood of which the quartzites are 
 much shattered and disturbed. Below the junction of the AUt an 
 Loin Mhor the quartzite is far less schistose in character, and at 
 Delyorn becomes a massive rock showing hardly any traces of 
 movement. Bands and thin seams of miea-schist or fine-grained 
 gneiss are freely intercalated with the quartzites, and are sometimes 
 of sufficient breadth to be indicated on the map, as at the Hill of 
 Knocktulchan. A similar section is afforded by the AUt Gheallaidh, 
 but here the rocks are much concealed by drift along the upper part 
 of the stream. Compressed folding in the quartzite is well seen in 
 this section at the foot of Paul's Hill, and also a short distance 
 
Metamorphic Bocks. 27 
 
 above Pitchroy Mill. At the latter locality a band of grey mica- 
 schist with small knots or aggregations is folded with the quartzites. 
 These siliceous strata can also be observed at several localities 
 along the course of the Spey, as at Dalvey, Tulchan Lodge, 
 Achvochkie, the Craigs of Callander, and Delnapot. A good 
 section is laid bare on the western side of the Pool of Bundearg 
 immediately below the junction of the Avon with the Spey. Here 
 massive, banded, purplish quartzites alternate with cleaved mica- 
 schists. The dark bands in the quartzite distinctly indicate lines 
 of original bedding, and the cleavage planes in the schist, which 
 are oblique to the other divisional planes, do not pass into the former 
 rock. Below Dalgarvon, where the river takes a sudden bend to the 
 east, the rocks become more gneissose in their general character. 
 Fine-grained granulitic biotite and muscovite-biotite gneisses, with 
 occasional intercalations of more siliceous rock, appear at Knockando 
 House, Laggan, and several other points along the course of the 
 Spey between the mouth of the Knockando Burn and the western 
 boundary of the Ben Einnes granite. L.W.H. 
 
 Undifferentiated Schists. 
 
 From Knockando northwards to the Black Burn beyond Dallas, 
 the metamorphic rocks consist of quartzo-micaceous-schists, with 
 broad bands of muscovite-biotite-schist which have been separated 
 out from the more siliceous rocks. In the north-west corner of the 
 map there is a small area of holocrystalline felspathic quartzite. 
 The west end of the Eildon Hill is composed of a very hard pink 
 quartzite alternating with micaceous flaggy bands, and, associated 
 with these, a belt of grey flaggy mica-schist stretches from Eafford 
 to the Monaughty Wood. This rock is a coarse flaky muscovite- 
 biotite-schist or gneiss, with wavy folia. It often contains garnets, 
 and is extremely rich in mica, and in its lithological character closely 
 resembles the muscovite-biotite-gneiss which has been separated 
 from the Moine schists in the survey of the Central Highlands. 
 
 The rocks around Westerton House, Black Burn, are flaggy 
 quartzose and micaceous schists with bands of pink quartzite, and 
 similar massive pink quartzites with pegmatite veins form the 
 rocky slopes which surround the water reservoir at Farnaley. To 
 the south of Blackhillock, near the head of the Black Burn, there 
 are fine flaggy quartz-schists with colour-banding parallel to the 
 foliation planes, which are intersected by small granite dykes and 
 veins. These schists lie between two broad belts of muscovite- 
 biotite-gneiss, massive and tough in character, and containing 
 numerous lenticles and strings of quartzo-felspathic material 
 developed along the foliation planes. 
 
 Very little rock is seen in the valley of the Lossie, but its tributary, 
 the Lennoc Burn, affords a good section for several miles. At the 
 head of the stream flaggy gneisses with several bands of crumpled 
 muscovite-biotite-gneiss are inclined to the north-west at an average 
 angle of 25°, and are succeeded by a series of hard, grey, massive 
 quartzites and quartz schists with small granite veins. The Glen- 
 
28 Explanation of Sheet 85. 
 
 latterach waterfall is produced by a very massive band of quartzite 
 dipping to north-east, over which the stream precipitates itself into 
 a ravine whose sides are formed by rocky cliffs 100 feet in height. 
 For some distance below the cascade the beds are vertical, but 
 lower down, towards the mouth of the stream, dip north and north- 
 west at 20° to 60°, and are chiefly grey gneissose flags with colour 
 banding parallel to the foliation planes. Below the crofts of 
 Buinach the river Lossie flows for some distance over a rocky floor 
 composed of hard, grey, massive and flaggy quartzites. In the 
 Gedloch and Shougle Burns, east of the Lossie, the beds are holo- 
 crystalline, granuhtic, micaceous flagstones, with bands of hard, 
 massive quartzite. At the upper end of the "Slogg " of Gedloch 
 the rock face of the ravine shows a fine pink quartzite very much 
 brecciated, and not unlike the " Cone Eock " at Eothes. 
 
 Between Birchfield and east of Hart Hill the rocks along the line 
 of the Glen Eothes fault are very much disturbed and shattered, 
 and are mainly composed of pink and dark grey massive quartzites 
 with, bands of more micaceous material. These are uniformly 
 holocrystalline and granulitic in structure, and are associated with 
 numerous small bands and one broad belt of muscovite-biotite- 
 gneiss. 
 
 In the Back Burn of Eothes massive quartzites and quartz-schist 
 veined with granite are inclined to east and south-east, and 
 apparently overlie a band o£ very fine light-grey muscovite- 
 biotite-gneiss with small garnets, which is succeeded by grey 
 micaceous flagstones with veins of granite and quartz. About a 
 mile to the west of the village the Eothes Burn runs between high 
 clifis of rather decomposed flaggy micaceous schist, often very 
 gneissose, and traversed by numerous small quartz and granite 
 veins. Above Doony Hall the rock passes into muscovite-biotite- 
 gneiss traversed by numerous dykes, veins, and lenticles of granite, 
 and within half-a-mile of the Netherly diorite it is pierced by 
 several small bosses of pink granite. In the burn of the Coulatt 
 there is an outcrop of drab-grey, very fine-grained quartzites. These 
 are distinctly bedded, and in some cases show false bedding oblique 
 to the ordinary planes of deposition. 
 
 Dr. Mackie* of Elgin has made an elaborate investigation of 
 the granite veins and contact rocks of the Back Burn of Eothes. 
 Chemical analyses were made by Dr. Mackie from five veins (2 
 biotite-bearing veins, and 3 muscovite-bearing or pegmatite veins), 
 and specimens were selected from the centre and margin of the veins 
 along with "proximal" and "distal" specimens from the quartz-schist 
 alongside. The general results obtained -were that the marginal 
 zones of the veins are considerably more basic than the centre, and 
 in the marginal rocks the " proximal " specimens are more basic 
 than the " distal " ones. The veins are also richer in potash at their 
 margins than in the centres, and in the contact rocks there is a 
 marked excess of this element in the " proximal " as compared with 
 the " distal " analyses, indicating an outward flow of potash. 
 
 J. S. G. W. 
 
 * Trans. Edinburgh Geol. Society, Vol. viii., Part i., p. 98. 
 
Igneous Bocks. 29 
 
 CHAPTER VI. 
 
 IGNEOUS BOOKS. 
 
 The igneous rocks found within the area under consideration may 
 be conveniently arranged in two classes, according as they are 
 shown by their structure to be earlier or later than the earth move- 
 ments that have affected the schistose rocks of the region. 
 
 The older plutonic intrusions of acid type consist of foliated 
 muscovite-granite or augen gneiss ; the basic rocks are represented 
 by sills of foliated gabbro, epidiorite, and serpentine. The newer 
 igneous masses include the great central area of the Ben Einnes 
 granite with its apophyses and marginal basic modifications on the 
 north-east; the small tract of unfoliated quartz-mica-diorite and 
 serpentine in the extreme south-west corner of the map ; a few later 
 dykes of lamprophyre; and a contemporaneous andesite of Old 
 Eed Sandstone age. L. W. H. 
 
 1. Oldee Plutonic Masses. 
 
 Epidioeites. — The general character of the epidiorite in this sheet 
 is that of a fine-grained crystalline rock. It varies in colour from 
 light to dark green, and in several localities contains garnets. It 
 occurs in the Deveron Valley in small separate bosses and also as a 
 portion of the western margin of the large Huntly area (sheet 86). 
 In the Blackwater and Glen Markie sections there are numerous 
 small sills of this rock. From the foot of the burn of Edinglassie 
 in the valley of the Deveron to the Westerfolds, a small tongue of 
 the large epidiorite area to the east enters this sheet. A specimen 
 from Westfolds shows the rock to be afine-grained dark green foliated 
 epidiorite or hornblende schist. At the foot of the burn of Eding- 
 lassie this rock becomes very massive and has all the appearance of 
 an altered rock with contact minerals. It is quite possible that the 
 foliated granite at Quarryhead may have been the cause of this 
 alteration. Further up the Deveron, near Wallakirk, there is a 
 similar area of epidiorite which when traced to the south-west 
 passes into the serpentinised gabbro of Craigs of Succoth and 
 Craigdomey. In the Markie Water section numerous small sills 
 and masses of epidiorite with garnets are intercalated with the 
 black-schists and limestone of Glen Markie. At the Newton of 
 Glen Markie the rock is very massive and fine grained. In the 
 burn which runs past the farmhouse of Findouran there is an 
 exposure of a grey green very finely foliated hornblende schist which 
 appears along the edge of the belt of gabbro (No. 9565, see Chap. 
 VII.). 
 
30 Explanation of Sheet 86. 
 
 Gabbko. — At Oraigs of Succoth this rock produces bold craggy 
 features on both sides of the river. At Craigdorney it is a 
 medium-grained dark grey peridotite, partially serpentinised in 
 places. It consists principally of diallage and olivine, the latter 
 mineral in places still remarkably fresh (No. 9563, see Chap. 
 VII.). On the east side of the Brown Hill the three craigs of 
 Belcherrie, Succoth, and line rise above the surrounding turf-peat 
 and heather, and consist chiefly of dark green serpentine with a 
 little gabbro. To the south this serpentine passes into a gabbro. 
 
 J. S. G. W. 
 
 The river Black water, from its junction with the Deveron to the 
 edge of the map, affords a good section of the series of basic sills 
 which form the northern prolongation of the sill of gabbro and 
 epidiorite that crosses sheet 75, and has been fully described in the 
 explanation accompanying that sheet. 
 
 These rocks, though considerably altered, belong generally to the 
 pyroxene rather than to the amphibole group. The most basic 
 portions are more or less serpentinised, though this form of altera- 
 tion is not so complete as in the masses of serpentine seen around 
 Blackwater Lodge, a mile or two further south. Microscopic 
 examination of some of these serpentines shows that they have 
 resulted from the decomposition of pyroxenes (see Chap. VII.). In 
 other cases the serpentine has possibly been derived, by a process 
 of selective metamorphism, from the olivine-bearing portions of the 
 gabbro. Original crystals of olivine can still be occasionally 
 recognised in the former rock, while this mineral appears to be 
 absent from the gabbro where the latter shows no trace of 
 serpentinization (2963, 2964). 
 
 Gabbko. — The broad sill that follows the course of the Blackwater 
 from the point where it bends to the south to the edge of the sheet 
 is composed of a partially uralitised gabbro. Under the micro- 
 scope the rock appears as a holocrystalline aggregate of plagioelase 
 and augite, the former being the predominant constituent. The 
 augite, which is a diallagic variety, occurs in irregular masses and 
 grains sometimes enclosed within the plagioelase, and is mostly of a 
 turbid brown colour. Along the periphery of the crystals it is 
 often altered into a fibrous green hornblende, which also occurs in 
 confused masses of fibres and minute needles. At the foot of the 
 small bum which joins the main stream on the west, rather more 
 than half-a-mile from the margin of the map, the rock is coarsely 
 crystalline, and contains large individuals of a greenish mineral. 
 Here also the augite is mostly altered into green or brown acicular 
 and fibrous hornblende, and it is these aggregates of actinolitic 
 hornblende which give rise to the green silky patches that are so 
 conspicuous in the rock. The wavy appearance of the strise of 
 some of the augites is suggestive of internal movement due to 
 extraneous pressure. 
 
 Parallel structure is everywhere more or less apparent in these 
 gabbros, but the foliation is more complete along certain bands 
 which, in the coarser portions of the rock, recall the beautiful 
 foliated gabbro of Pooldhulie in Strath Don. L. W. H. 
 
Igneous Rocks. 31 
 
 Foliated Granite. — ^The foliated granite to the west of Keith 
 occupies a long oval area which extends from Auchlunkart Lodge 
 to North Bogbain and embraces the upper portion of the Hill of 
 Mulderie. The best exposures of this rock are to be seen in several 
 small quarries to the east of Midtown and at the head of the small 
 burn which runs past CuUieshangan. At the former locality the 
 foliation planes are inclined E. 28 S. at 45°, The rock is 
 partially decomposed and is a light-brown coarse granitoid mica- 
 ceous gneiss with more or less isolated and drawn-out augen- 
 shaped masses or kernels of felspar. (Some notes on its microscopic 
 characters will be found in Chap. VII.) 
 
 To the east of Fife-Keith on the banks of the river Isla, and in a 
 quarry between the railway station and the edge of the sheet, there 
 are good exposures of a belt of foliated granite identical with that 
 seen at Mulderie. The foliation planes vary considerably in their 
 direction from E. 5 N. to S. 8 W. with an average angle of 30". 
 Parallel to this band and about 400 yards to the east a similar 
 zone extends from near Coldhome to the north-east of Keith, and is 
 in all probability the Fife-Keith belt repeated by folding. The 
 best section is seen in the quarry to the south of the Eoman 
 Catholic Chapel, where the rock is a fine-grained silvery grey gneiss. 
 
 Between the Carran and Bellyhack Hills the ground is covered 
 with numerous angular blocks of this foliated granite, and although 
 no rock is actually seen in place its presence is inferred from the 
 abundance of the loose debris. The quarryhill to the west of 
 Invermarkie is also covered by debris of augen gneiss. 
 
 J. S. G. W. 
 
 Newer Plutonic Rocks. 
 
 Granite. — The great central mass of granite forms two areas of 
 unequal size lying on either side of the river Spey. They are 
 probably continuous beneath the alluvium immediately opposite 
 Aberlour, but between the mouth of the Ruthrie Burn and Laggan 
 are separated at the surface by a thin strip or bridge of meta- 
 morphic rock which is seen in the steep northern bank of the river. 
 
 The larger area south of the Spey covers nearly 24 square miles 
 of ground between Ben Rinnes and Dufftown. Its longer axis 
 extends for six miles in a north-east direction, parallel to the strike 
 of the schists. The northern mass occupies an area three miles by 
 two in extent, of which the village of Archiestown is the centre. Its 
 exact limits are somewhat uncertain, the position of the 
 boundaries being generally obscured by drift. The boundary line 
 drawn along the slopes of the Hunt and Stob Hills is indeed only 
 an approximate one; since where the ground, as on the summit of 
 Hunt Hill, is bare of drift it presents a plexus of igneous and 
 metamorphic rocks, the interlacing veins and apophyses from the 
 main mass of granite traversing and isolating portions of the sur- 
 rounding schists in a most complex manner. That this is the 
 nature of the junction all along the northern boundary of the 
 granite is indicated by the innumerable veins seen in all the stream 
 sections and wherever the rocks are exposed. 
 
32 Explanation of Sheet 85. 
 
 In none of these intrusions is there any appearance of a chilled 
 edge ; indeed the thin veins are as coarsely crystalline up to their 
 margins as the interior portions of the main mass. The veins have 
 usually been injected more or less along the planes of foliation, 
 but occasionally a broader vein is seen to cut these latter at a high 
 angle, sending out thin branch veins on either side along the planes ' 
 of schistosity. 
 
 In addition to this direct introduction of igneous veins, the 
 rocks along the granite border are often so much impregnated 
 with granitic material that the structure becomes granitic rather 
 than granulitic. This phenomenon is particularly noticeable at the 
 bridge of Craigellachie and in the railway cutting close to the 
 station, where this interstitial permeation is so complete that it is 
 often difficult to distinguish the altered quartzite from the original 
 igneous rock. 
 
 Quarries have recently been opened on the northern flanks 
 of the Blue Hill of Aberlour, a few hundred yards from the northern 
 edge of the Ben Einnes granite, the intervening ground being filled 
 with veins and apophyses from this igneous mass. The rock 
 exposed in the quarries is a granulitic muscovite-biotite-gneiss or 
 schist, generally fine grained and tolerably siliceous, but with 
 occasional coarse and more gneissose bands. It is filled with 
 parallel veins or bands of granitic quartzo-felspathic material 
 varying from less than |-inch to one foot in thickness. They are 
 generally parallel to the foliation-planes of the schist, but 
 occasionally send branches or strings across from one vein to 
 another. The thicker veins tend to become coarser in the centre, 
 but nothing like a chUled edge exists, and an interlocking of the 
 marginal crystals of the vein with those of the surrounding schist 
 can often be detected. 
 
 Certain of the veins swell out at intervals into lenticular or eye- 
 shaped masses, some of which seem to be isolated from one another, 
 while others are connected by a thin string of the same material. 
 These " augen "-like masses are generally sheathed or surrounded by 
 thin bands in which biotite is considerably more abundant than in 
 the rest of the rock ; suggesting a separation of the more acid from 
 the ferro-magnesian minerals along certain lines. 
 
 While the direct intrusion of granitic material along the lines of 
 discontinuity in the schists has usually been suggested as the cause 
 of these phenomena, it is possible that they may also be due to 
 segregation of the quartzo-felspathic elements in the surrounding 
 rock. Whether we attribute these appearances to direct intrusion, to 
 segregation, or to a combination of both causes, we may with 
 certainty assume that they are intimately connected with the 
 period of intrusion of the Ben Einnes granite, and are of later origin 
 than the movements which produced the schistosity of the rocks in 
 which they appear. 
 
 The principal constituents of the ordinary type of Ben Einnes 
 granite are quartz, orthoclase and oligoclase felspar, and biotite ; the 
 last named mineral being generally scanty, and sometimes altogether 
 absent. Varieties of the granite also occur in which microcline, 
 muscovite, sphene, and allanite are present (see Chap. VII.). 
 
Igneoios Bocks. 33 
 
 The differentiation of the original magma of the Ben Rinnes 
 granite seems to have proceeded on similar lines to that observed in 
 connection with many other intrusive masses in the Eastern and 
 Central Highlands. Intrusions of basic rock are represented on the 
 map as occurring along the burn of Eothes at Netherly and on the 
 Hill of Stob, immediately to the north of the granite area of 
 Archiestown and the Hunt Hill. On the Hill of Stob the rock is a 
 typical diorite of which the essential constituents are hornblende, 
 biotite, and plagioclase ; at Netherly we find a more acid type, a 
 moderately coarse-grained quartz-biotite-diorite, in which the biotite 
 often occurs in very large individuals. Both varieties are thoroughly 
 granitoid in character and show no signs of alteration or paralle 
 structure. The bed of the burn of Eothes is filled for a distance of 
 nearly a mile with large sub-angular masses of the mica-diorite, but 
 the rock is only seen actually in place at one point near the western 
 limit of the area. The Hill of Stob diorite also only occurs in large 
 weathered blocks on the surface, but there is strong presumption 
 that the rock is in place below. 
 
 The mutual relations of these two basic masses, and of both with 
 the granite of the Hunt Hill, cannot be clearly determined, the 
 intervening ground being so thickly covered with drift that no rock is 
 seen even in the stream sections ; but the similarity in condition of 
 crystallisation and of structure is in favour of their origin from a 
 common magma, and of their continuity beneath the superficial 
 covering. 
 
 The surface of the ground on the wooded hilltop above the Cone 
 Rock, south of Rothes, is thickly strewn with masses of diorite. 
 probably weathered out in place, though the rock is nowhere 
 actually seen in situ. The chief constituents of this rock are 
 felspar, green hornblende, and quartz, with sphene as an abundant 
 accessory ; and from the amount of orthoclase present it may be 
 regarded as a syenite. Another small exposure of a somewhat 
 similar rock is seen along the roadside between Dandaleith Station 
 and the Bridge of Craigellachie. It varies a good deal in character. 
 The prevalent type is quartz-diorite, in which orthoclase is always 
 present, and sometimes in such abundance that the rock becomes a 
 syenite. 
 
 These varieties from the two localities described above have been 
 regarded as intermediate or passage forms between the Netherly 
 diorite and the granite of Hunt Hill and Ben Rinnes ; and the 
 evidence afforded by the microscopical examination, as adduced in 
 the Petrographical chapter, serves strongly to support the conclusions 
 arrived at during the field work. 
 
 The granite of Ben Rinnes is closely similar both in character 
 and mineral composition to the granite of the Cairngorm Moun- 
 tains. The differentiation of the magma, as already indicated, is 
 also similar to that found along the southern margin of the 
 Cairngorm granite ; where the same passage from biotite granite 
 through syenite or tonalite into typical diorite has been described 
 from G-len Gairn and Upper Deeside.* The marginal phenomena 
 
 * Geol. Survey Summary of Progress, 1899-1900. 
 
 
34 Explanation of Sheet 85. 
 
 seen on Hunt Hill and round CraigeUachie also strongly recall the 
 complex system of apophyses, inclusions, and detached veins observed 
 along the edge of the Monadhliath granite mass at Aviemore, and 
 at Loch Builg in the Eastern Cairngorms. 
 
 Owing to the want of exposures, the contact zone of the Ben 
 Einnes granite and the Banffshire series affords little evidence of 
 thermo-metamorphism ; but in the region north of the Spey the 
 Netherly diorite has produced hornfelsing in those portions of the 
 surrounding schists that were from their original composition 
 capable of being altered in this manner. The minerals found in 
 the andalusite and cordierite-hornfels in the burn of Eothes are 
 essentially the same as those of the cordierite rocks near the 
 Cairngorm granite in sheet 75 {see Chap. VII.). Another 
 characteristic feature of the Cairngorm granite is found in the 
 " scurrans " or weathered rock-masses that crown the summit of 
 Ben Einnes and show well-marked tabular weathering along their 
 horizontal joints. 
 
 The facts adduced above show the striking resemblance in 
 composition, variation, and relations with the surrounding rocks 
 that exist between the Ben Eiimes and Cairngorm granites, and 
 indicate the close relationship of the two masses. It therefore 
 seems highly probable that the former, as well as other outlying 
 masses to the north and west, belong to the period of intrusion of 
 the great granite area in the south ; and further, may, as suggested 
 some years ago in the explanation to sheet 75, be regarded as 
 protrusions from an underlying and continuous floor of igneous 
 rock. 
 
 Along the banks of the Spey at Carron, Dalmunach, Pool Leek, 
 and Creag Neach ; in the cutting under Knockando House ; and 
 beneath the alluvium near Dalbeallie Station, the quartz flagstones 
 are pierced by numerous veins and sills of red granitite containing 
 orthoclase, oligoclase, quartz, and abundant biotite. In the crag 
 that overhangs Pool Leek the junction between the two rocks is 
 well seen. The quartzite at the water's edge rests upon the upper 
 surface of a sill of granite which is coarse-grained to the edge and 
 shows no sign of a chilled margin. A small outlying mass of the 
 Ben Einnes granite is also found at Parkhead, half-a-mile north of 
 Glen Farclas Distillery. It contains inclusions of quartz-schist, but 
 is much decomposed, and is quarried at the roadside for sand. 
 
 Diorite. — ^The small patch of basic igneous rock that crosses the 
 extreme south-east corner of the map at Three Burnshead How, 
 forms part of a large area of quartz-mica-diorite lying to the south 
 of the Tap of Noth in the adjoining sheets (76,86). It is a coarse 
 granitoid rock of which the essential constituents are quartz, 
 plagioclase, biotite, and hornblende, with no signs of parallel 
 structure, and shows the characteristic weathering into spheroidal 
 masses common to so many of the Aberdeenshire diorites. The 
 serpentine that appears on the east side of the diorite is possibly an 
 altered ultra-basic modification of the same intrusion, but the 
 boundary and relations between the two rocks are obscured by the 
 thick covering of boulder-clay. 
 
Igneous Rocks. 35 
 
 The evidence is in favour of separating these rocks from the 
 foliated epidiorites and gabbros of the Deveron and Blackwater, and 
 assigning them to a later period of intrusion. 
 
 Lampeophyee. — In the quartz-schists that form the steep cliff 
 that rises above the Spey at Hollybush Pool, about three-fourths of 
 a mile east of Aikenway, there are three or four thin sills of a fine- 
 grained greenish-red basic rock generally much decomposed. The 
 rock is indicated on the map as a camptonite, but from its character 
 under the microscope it is regarded by Dr. Flett as a dioritic 
 lamprophyre. The microscopic characters and systematic position 
 of this rock are discussed in Chapter VII. L. W. H. 
 
36 Explanation of Sheet 85 , 
 
 CHAPTER VIL 
 
 PETROGRAPHY OF THE AREA. 
 
 I. The Later Granites and Diorites. 
 
 Of the newer granites which date from a period subsequent to 
 the development of the foliation, and hence present the usual 
 structures of plutonic igneous masses, only one great mass exists 
 in this area, that of Ben Rinnes and the Convals. The smaller 
 intrusions at Netherly, Dandaleith, etc., though more basic in 
 character, show so many evidences of consanguinity to the more 
 acid tjrpe that they are best regarded as its marginal modifications. 
 A complete series of gradations from the most acid muscovite 
 pegmatites to the quartz-augite-diorites can be traced in the 
 microscopic sections, and leaves no room for doubt that they have a 
 genetic relationship. A similar association is well known in the 
 granite of the Cairngorms,* the Southern Uplands,t Garabal Hill,+ 
 and elsewhere in Scotland. 
 
 The Ben Rinnes granite, as seen on the northern slopes of that 
 mountain and in the vicinity of Aberlour, is mostly a flesh-coloured 
 biotite granite, of medium grain and rich in quartz ; while biotite, 
 the only dark-coloured ferro-magnesian silicate, is never present in 
 great quantity, and is sometimes almost absent. Both in the hand 
 specimens and under the microscope it closely resembles the Cairn- 
 gorm granite, of which it is in all probability an outlying mass. 
 Its principal ingredient is a flesh-coloured felspar, which occasion- 
 ally shows a tendency to porphyritic development, and proves to be 
 mostly orthoclase with subordinate oligoclase. Microcline is not 
 common, the orthoclase is often perthitic and surrounds the acid 
 plagioclase ; muscovite is very scarce, and for the most part 
 secondary. A little micropegmatite (quartz vermicule) is not 
 infrequent. Occasionally the hand specimens show an ill-defined 
 parallel structure, and under the microscope traces of cataclastic 
 action are rarely entirely absent. 
 
 Taken as a whole, the Ben Rinnes granite is exceedingly uniform 
 throughout, but towards the margins of its outcrop varietal 
 modifications of several kinds occur. Thus in the quff,rry at 
 Ruthrie, Aberlour, a grey granite is obtained, obviously richer in 
 biotite than the granite of Ben Rinnes, from which also the pearly- 
 white or grey colour of its felspar distinguishes it. This granite 
 
 * Memoirs of the Geological Survey, Scotland. Explanation of Sheet 75 by Lionel W. 
 Hinxman, B.A., with a Fetrologioal Chapter by J. J. H. Teall, M.A., F.E.S. 1896. 
 
 f Memoirs of the Geological Survey. The SUurian Rooks, Vol. i., Scotland. By B. N. 
 Peach, r.R.S., and John Home, P.R.S. 
 
 JThe Plutonic Rooks of Garabal Hill and Meall Breac, by J. J. H. Teall, F.R.S., and 
 J, R. Dakyns, Quart. Jour. Geo). Soc, Vol. xxviii., p. 104. 
 
Petrography of the Area. 37 
 
 is rich in sphene and allanite, the cherry-red grains of the former 
 and black or coffee-brown prisms of the latter being easily detected 
 on the surface of the hand specimens with the aid of a pocket lens. 
 The sphenes are often in interpenetrating cross twins ; the allanite 
 in elongated dark-brown, zonal prisms, sometimes simply twinned 
 on the orthopinakoid and slightly pleochroic. They are j)erfectly 
 idiomorphic, the transverse sections being bounded by the usual 
 six faces (001, 101, 100) and resembling hornblende in their out- 
 lines. This rock contains much oligoclase, perthitic orthoclase, and a 
 little micropegmatite. The sections show no muscovite, and no 
 cataclastic structures. 
 
 Allanite occurs also in the granite which forms a little mass at 
 Carron on the Spey. In the rock slice one large prism is seen in 
 longitudinal section. It has a dark-brown colour, and is highly 
 zonal. The rock is a reddish biotite granite, not unlike that of Ben 
 Rinnes but richer in biotite. 
 
 The muscovite granite of Nether Cluny, two miles S.S.W. of Duff- 
 town, is of quite a different type. It is probably a vein or apophysis 
 of the main mass, and is exposed in a small stream by the roadside in 
 contact with a quartzite. Biotite is absent; muscovite, which is 
 scarce in the Ben Rinnes granite, is here abundant, and the felspar 
 is largely microcline. The rock is pale coloured, of medium grain, 
 and the numerous plates of muscovite scattered over their surfaces 
 give the hand specimens a very characteristic appearance. The 
 quartz and felspar tend to occur in rather coarse graphic inter- 
 growth. In the points in which it differs from the typical granite of 
 Ben Rinnes, this rock approaches the aplites and muscovite pegma- 
 tites, of which there are many examples in the dykes of this region. 
 
 Hornblende has not been detected in the Ben Rinnes granite, 
 with one interesting excejrtion. A section was prepared from a 
 small, rounded, dark coloured, fine-grained inclusion in a mass of 
 granite at Milltown of Ruthrie, above Aborlour. It proved to be 
 an intimate admixture of hornfelsed biotite gneiss with veins of 
 diorite. Each of the two rocks preserves its characters, though the 
 schist is surrounded and penetrated hj the diorite. The latter is 
 rather fine grained, rich in orthoclase and in sphene, which often 
 encloses well formed, lath shaped plagioclase felspars, . and in one 
 crystal shows lamellar polysynthetic twinning parallel to the face 
 of the prism (110). Hornblende is mostly idiomorphic, only rarely 
 enclosing a felspar. Biotite, which is abundant in the schist, is 
 practically absent from the diorite. In these features this rock 
 clofsely resembles the syenites and diorites, which we now pass to 
 consider. 
 
 At Dandaleith Station, along the roadside, half way to Craigel- 
 lachie Bridge, there is a limited exposure of a dark-colovired 
 dioritic rock, of which the principal ingredients are dark green 
 hornblende, and flesh-r'.oloured, or sometimes brick-red felspar. 
 From this little mass several specimens were prepared, and as 
 might be suspected from the hand specimens, it is not altogether 
 uniform in character. The prevalent type is a quartz-diorite, con- 
 sisting of green hornblende, plagioclase felspar, and varying 
 
38 Explanation of Sheet 85. 
 
 amounts of quartz. The structure is not ophitic, the hornblende 
 having crystallised before the felspar, which it does not enclose. 
 But orthoclase is never absent, and in some of the sections it is 
 the dominant felspar: the rock might then be regarded as a 
 syenite. The sections show no biotite : reddish pleochroic sphene 
 is abundant and conspicuous in the hand specimens. It occurs in 
 large ophitic plates, enclosing lath-shaped plagioclase felspars, and 
 has a very perfect lamellar structure, which is evinced by straight, 
 perfectly continuous cleavages parallel to the prism fac3S (HO). 
 This structure has usually been ascribed* to repeated twinning, 
 and between crossed nicols it is obvious that the crystals are poly- 
 synthetic, the sections being crossed by numerous colour bands 
 which run parallel to the cleavage, and may be in two series 
 intersecting one another. Epidote is abundant in this rock, and 
 has sometimes brown cores, which may be allanite. Stout, hexa- 
 gonal prisms of apatite are frequent, and a few are crowded with 
 minute dark enclosures, but these are far more characteristic of 
 the diorite of Netherly. 
 
 In the wood above the Cone Eock, one mile south of Eothes, large 
 blocks of diorite lie strewn over the surface of the ground, probably 
 weathered out of a subjacent mass. This rock contains much grey 
 felspar, abundant dark-green hornblende, and no biotite. It 
 contains a fair amount of quartz, and so much orthoclase as to 
 entitle it to be regarded as a syenite. Sphene is abundant, 
 occasionally enclosing a felspar, t and shows the lamellar platy 
 sti'ucture, with only traces of polysynthetic twinning. The horn- 
 blende is rather decomposed, chlorite and epidote being the 
 products. 
 
 The diorite of Netherly is well exposed in the Rothes Bum, 
 and is in the hand specimen a handsome rock with hornblende, 
 black glancing biotite, and greyish quartz and felspar, of medium 
 or rather coarse grain, and not porphyritic. It is a more normal 
 diorite than those already described, as plagioclase, zonal and 
 sometimes fairly basic, forms its principal felspar, though ortho- 
 clase is present in quite subordinate amount. The biotite some- 
 times encloses plagioclase, the hornblende as a rule does not. A 
 little grey-green pyroxene occurs, enveloped in dark green horn- 
 blende. The one mineral is often found to enclose patches of the 
 other, each then extinguishing simultaneously throughout, and 
 probably they are in parallel intergrowth. In many cases the 
 hornblende has paler centres, giving it a spotted appearance, and 
 it is in every way probable that augite originally formed the cores 
 of such crystals. The hornblende is similar in character to that 
 in the diorite of Dandaleith, the augite shows no diallage lamina- 
 tion. Sphene is less frequent in this rock, and usually forms thin 
 
 * Williams, G. H. Cleavage in American Sphene. American Journal of Science,. 
 Vol. xxix., p. 486 (1885). 
 
 Mugge, 0.- Ueber durch Druch entstandene Zwillinge vou Titanit. Neues Jahrbuoh 
 fnr Mineralogie (1889), Band ii., p. 98. 
 
 Lawson, A. E. The Eainy Lake Region. Ann. Report of the Geol. Survey of 
 Canada (1887), Pt. i., p. 124, Pig- H- 
 
 fMackie, W. On Differences of Composition between the Central and Marginal 
 Portions of Granitic Veins. Trans. Edin. Geol. Soc, Vol. viii., Pt. i., p. 94. 
 
Petrography of the AreM. 39 
 
 rings around iron oxides. Apatite is very ^abundant in large, 
 stout, idiomorphic prisms, which are so filled with little dark 
 enclosures as to become quite opaque at their centres, while 
 sometimes a thin external zone is perfectly clear and transparent. 
 As a rule, these enclosures are too small to reveal their nature 
 even under the highest powers, but the largest of them are fluid 
 cavities with mobile bubbles. These apatites are not pleochroio, 
 but similar crystals occur in a small intrusive mass or large vein 
 which pierces the schists a little east of Craigellachie tunnel, and is 
 exposed ' in the railway cutting ; and here the pleochroism is 
 marked, and as the nicol is rotated the section changes colour 
 from pale yellow-brown to dark greyish-blue or black. Such 
 apatites are more frequent in volcanic than in plutonic rocks. 
 
 The quai'tz of this diorite is often filled with dark hairs of 
 riitile, a feature which constantly recurs in the plutonic masses in 
 this area. The felspars also contain minute opaque enclosures 
 regularly disposed in at least two series, with a definite orienta- 
 tion which could not be exactly determined. These, it may be 
 pointed out, are characteristics also of the more basic rocks 
 associated with the Galloway granites, to which the Elginshire 
 diorites present a strong resemblance. 
 
 At Stob Hill, a little south of Netherly, a diorite is exposed, 
 essentially similar to that just described, except in the greater 
 abundance of biotite, which gives the rock a distinctive appearance. 
 Here, too, sphene is not abundant ; the apatites have numerous 
 large fluid cavities, but are not dusty and opaque ; the hornblende 
 has often paler centres, which may have originated from a pyroxene, 
 though that mineral was not present in the rock section. The 
 felspars contain the regularly arranged opaque enclosures. 
 
 In the quartz diorites of Netherly and Stob Hill it is frequent 
 to find the hornblende in spongy masses, the interstices of which 
 are filled up with quartz or acid felspar (see Fig. 1). The 
 structure is micropoikilitic, or often graphic, as the scattered 
 patches of quartz may extinguish simultaneously. They may, 
 moreover, be in optical continuity with areas of quartz surrounding 
 the hornblende and filled with fluid cavities and rutile hairs. This 
 is sufficient to establish the identity of the mineral, which is dis- 
 tinguished also from apatite and early basic plagioclase by its index 
 of refraction. 
 
 The periods of crystallisation of the hornblende and the quartz 
 were too vddely separated to allow us to suppose that this is a 
 graphic intergrowth due to simultaneous crystallisation. The 
 hornblende had practically ceased to form before the plagioclase 
 felspar had started, and the latter in its turn entirely preceded the 
 quartz. A similar relationship between these two minerals has 
 been described by Eomberg,* who compares it with the contact 
 structures described by Salomont and others. It may, however, be 
 
 * Romberg, J. Petrographisohe Untersuohungen an Diorit, Gabbro, uud Amphi- 
 bolgesteinen. Neues Jahrbuch fur Mineralogie, ix. Beikge Band (1894), p. 307. 
 
 t Salomon, W. Ueber einige Binschlusse metamorpher Gtesteine im Tonalit. Neues 
 Jahrbuch fur Mineralogie, vii. Beilage Band (1891), pp. 482, 483. 
 
 Salomon, W. Geologisohe und Petrographisohe Studien am Monte Aviolo inltalienischen 
 Antheil der Adamellogruppe. Zeits. derdeutschen Geol. Gessell., B. 42. (1890), j>. 450. 
 
40 Explanation of Sheet 85. 
 
 much more probably ascribed to corrosion, as in a case described by- 
 Milch in his paper on the Granitic Rocks of the Riesengebirge,* 
 where he discusses the origin of a similar relationship between 
 biotite and quartz. In the Elginshire rocks the biotite has 
 indeed been corroded, but to a much less extent than the horn- 
 blende, which is often perfectly honeycombed. 
 
 Corrosion of the hornblende occurs only in the presence of 
 biotite, as, in the diorites of Dandaleith and the Cone Rock, where 
 biotite is absent, the hornblende is always compact. Some of the 
 hornblendes in the Netherly diorite are quite unaffected, and those 
 most corroded are usually associated with biotite in such a way as 
 to suggest that by the rapid growth of the latter the magma had 
 been locally enabled to attack the hornblende. Where the two 
 minerals are clustei'ed together there is often between them a 
 narrow seam of quartz, representing the still fluid magma which 
 acted as the medium for a transfer of the molecules from one 
 mineral to the other. The quartz and felspar which fill the 
 cavities are quite full of small crystals of apatite and magnetite, the 
 characteristic enclosures of the hornblende. These are also, it 
 should be remarked, either very few or entirely absent from the 
 normal quartz of the rock. This has been noted as a feature of 
 minerals filling corrosion spaces by Backstromt and by Milch. + That 
 resorption did not begin till a comparatively late period in the con- 
 solidation of the rock is shown by the fact that where a crystal was 
 entirely enclosed by biotite it has escaped ; where protected only on 
 three sides the liquid magma has eaten its way into the crystal 
 from its exposed surface (Fig. 1). The material filling the cavities 
 is always the latest products of crystallisation, viz., quartz, ortho- 
 clase, and very occasionally an acid plagioclase (oligoclase). The 
 developmental history must have been somewhat as follows : — 
 Hornblende preceded biotite, and was followed by plagioclase 
 felspar, though the periods of formation of those three were not 
 absolutely consecutive but to a slight extent overlapped. The 
 magma, now highly acid and rich in alumina and the alkalies 
 (having in fact the composition of a eurite or aplite), corroded the 
 hornblende where exposed to its action, forming biotite partly at 
 its own expense, partly at that of the hornblende. 
 
 The formation of biotite from the corrosion of hornblende (and 
 also of pyroxene) by acid magmas, has been described by many 
 writers; among others by Becke,§ Sollas,|| Holland,^ Parkinson,** 
 
 * Milch, L. Beitrage xai Kenntniss der Granitisohen Gesteine des Riesengebirges, 
 Neues Jahrbuoh fur Mineralogie, xii. Beilage Band (1899), p. 145. 
 
 f Backstrom, H. Ueber fremde Gesteinseinschlusse in einigen skandinavisohen 
 Diabasen. Bihang till K. Svenska Vet-Akad. Handlingar, Bd. xvi., Part ii.. No. i. 
 Stockholm (1890). 
 
 X Milch, L. Beitrage zur Kenntniss der Granitischen Gestein des Riesengebirges. 
 Neues Jahrbuoh fur Mineralogie, xii. Beilage Band (1899), p. 145. 
 
 § Beoke, F. Petrographische Studien am Tonalit der Bieserferner. Tschermak's Min. 
 Petrog. Mittheilungen, Band xiii. (1892), p. 408. 
 
 II Sollas, W. J. On the Volcanic District of Carlingford and Slieve Gullion, Pt. i. On 
 the Relation of the Granite to the Gabbro of Bamavave, Carlingford. Trans. Royal Irish 
 Academy, Vol. xxx., pp. 477 and 494 (1894). 
 
 IT Holland, T. H. On Augite Dioriiie with Micropegmatite in Southern India. Quart. 
 Jour. Geol. Soc, Vol. liii., p. 405 (1897). 
 
 ** Parkinson, John. On an Intrusion of Granite into Diabase at Sorel Point (Northern 
 Jersey). Quart. Jour. Geol. Soc, Vol. Ivi., p. 340 (1900). 
 
Petrography of the Arm. 
 
 41 
 
 and Cole.* The spongy nature of the corrosion skeleton is paralleled 
 by the cases described by Backstrom,t Milch,t and Sollas. In the 
 granophyre of Barnavave the hornblende, which is largely after 
 pyroxene, is often completely riddled with quartz (Sollas). In the 
 basic modification of the granophyre of Carrock Fell the augite is 
 being replaced by green hornblende and other substances, and is 
 often in graphic intergrowth with felspar (Harker).§ 
 
 Fig. 1. Corroded Hornblende filled with Quartz. Quartz Diorite, Netherly, 
 Bum of Rothes, Elgin. (Section No. 9550.) 
 
 Most of the spongy hornblende belongs to one individual which in polarised_light 
 is seen to be repeatedly twinned. It is partly enclosed in biotite (stippled) 
 and plagioclase felspar, and these have protected it from corrosion. Towards 
 the centre of the figure and at the upper border it is in contact with quartz 
 which penetrates it in ramifying processes. These extinguish simultaneously 
 with the external quartz and enclose many small crystals of apatite and 
 magnetite. 
 
 There is nothing whatever to indicate that the corroded horn- 
 blende crystals in the Netherly diorite are xenocrysts. They have 
 all the appearance of original crystals which have crystallised out 
 from the magma. The intrusive rock has risen through a series of 
 quartzose Moine schists which contain no hornblende or augite, 
 and so far as is known, no igneous masses more basic than the 
 diorite itself. They may in part have resulted from the destruction 
 of pyroxene, but by far the greater number of them show no traces 
 
 *Co]e, 6. A. J. On Metamorphio Rooks in Eastern Tyrone and Southern Donegal. 
 Trans. Roy. Irish Acad., Vol. xxxi., Part xi., p. 431 (1900). 
 
 fBackstrom, H. Ueber fremde Geateinseinschlusse in einigen skandinavischen 
 Diabasen. Bihang till K. Svenska Vet.-Akad. Handlingar, Bd. xvi., Part ii., No. i. 
 Stockholm (1890). 
 
 J Milch, L. Beitrage zur Kenntniss der Granitischen Geateine des Riesengebirges, 
 Neues Jahrbuch fur Mineralogie, xii. Beilage Band (1899), p. 145. 
 
 § Barker, A. Carrook Fell : a Study in the Variation of Igneous Rock- Masses 
 Part ii. The Carrook Fell Granophyre. Quart. Jour. Geol. Soc, Vol. U. (1895), p. 125. 
 
4'2 Explanation of Sheet 85. 
 
 of such an origin. Rosenbusch has remarked that the principal 
 pause in the crystallisation of the diorites takes place after the 
 formation of the plagioclase felspars, and before that of the alkali 
 felspars and of the quartz. It is to this period that this action is to 
 be assigned. Examination of a series of sections of rocks of this 
 group has shown that this structure is by no means rare, though 
 not often so well developed as in the diorites under consideration. 
 
 The dykes which proceed from the granitic masses and intersect 
 the schists in the vicinity of Craigellachie and Eothes in great 
 numbers, are in most cases of a granitic character and show little 
 variation from the type of the parent mass. They are fine to 
 medium grained granites, not porphyritic, and without any chilled 
 edges. Some are rather basic and rich in biotite and sphene, 
 others more acid and approach aplites in composition. 
 
 In the gneisses and schists of the bum of Rothes, veins of a coarse 
 muscovite pegmatite occur. The felspar is oligoclase and an alkali 
 felspar which rarely shows microcline structure. A few small 
 rounded garnets are present. The muscovite is often stained dark 
 red by an infiltration of haematite along its cleavage planes. The 
 rocks show efiects of shearing. A curious feature of these dykes 
 is the presence of a string of quartz along its centre, indicating that 
 crystallisation proceeded inwards from the margins of the vein. 
 The quartz contains many large fiuid cavities with mobUe bubbles. 
 
 Only one rock of the lamprophyre group has been detected in 
 this area, indicated on the map as camptonite. It forms a thin 
 sill in the quartzites at Aikenway on the Spey, near Mulben. The 
 rock is rather fine grained, dark coloured, with small elongated 
 hornblende prisms, and reddened, decomposed felspar. Under the 
 microscope a greenish-brown hornblende is the most conspicuous 
 minei-al, in idiomorphic prisms, not greatly elongated. The trans- 
 verse section is bounded by the following faces, 110, 010, and 100, 
 the last only occasionally and very small. It is terminated by 001 
 and 111. It has the usual prismatic cleavage well developed, and 
 pleochroism ; — a, pale greenish yellow; h, brownish green; c, darker 
 green ; slightly brown. Twinning on the orthopinakoid is rare. 
 A pale green, almost colourless augite is present also, and like the 
 hornblende mostly free from enclosures. The two minerals are 
 often associated, but apparently not in parallel growth. The 
 pyroxene is fairly abundant, is not usually idiomorphic, and has 
 possibly suffered from corrosion, though traces of the prism and 
 pinakoids are sometimes visible in the transverse section. It is 
 much decomposed and filled with chlorite, serpentine (?), and calcite, 
 but when fresh gives brilliant polarisation colours, and has a high 
 angle of extinction (40° and over). Scattered through the felspar 
 there is much yellow epidote in little grains which do not appear to 
 have resulted from the decomposition of a second generation of 
 ferromagnesian minerals ; small hornblendes occur but they have 
 all the characters of the larger crystals, and a perfect gradation in 
 size can be traced, so that the rock is not porphyritic in the propei* 
 sense of the term. Felspar in long lath-shaped crystals, some- 
 what radially disposed, envelops the ferromagnesian minerals and 
 is of later formation, though not entirely, as sometimes a hornblende 
 
Petrography of the Area. 
 
 43 
 
 surrounds a felspar, to which it forms a narrow border. In 
 longitudinal section such hornblendes are " swallow tailed," with 
 hollow ends filled up with a felspar crystal. Most of the felspar 
 shows polysynthetic twinning, and appears to belong to andesine 
 and allied varieties, but in the thinnest parts of the section it is 
 obvious that orthoclase is present, surrounding the plagioclase, and 
 in places it is dappled like anorthoclase. The latest felspar is 
 intergrown in a rude graphic fashion with a sparing amount of 
 quartz, which forms also an interstitial material between the felspar 
 prisms. The accessory minerals are iron oxides, weathering to 
 leucoxene and limonite, and apatite in numerous long, pointed 
 needles. 
 
 This rock is obviously a dioritic lamprophyre, and in several 
 respects, more particularly in the presence of quartz as an 
 undoubtedly primary ingredient, is distinct from the typical 
 camptonites, which are among the most basic of all igneous 
 rocks.* It might perhaps be regarded as a basic Vogesite, but is 
 better assigned to the group of Spessartites which Rosenbusch has 
 established for vogesitic lamprophyres in which plagioclase is the 
 principal felspar. With the lamprophyres (spessartites) of the 
 Spessart as described by Goller it is almost completely identical. t 
 
 Dr. Mackie, of Elgin, has prepared an extensive and very 
 interesting series of chemical analyses which include several rocks 
 from this area. They will be found in the Transactions of the 
 Edinburgh Geological Society, Vol. VIII., Part I, 1901. Prom 
 these we take the liberty of quoting the following (I. to VIII.). 
 For a full discussion of their bearings on many important questions 
 in theoretical geology, the original papers should be consulted.J 
 
 1 !• 
 
 II. 
 
 III. 
 
 IV. 
 
 SiOg . . . '' 74-75 
 
 75-39 
 
 77-18 
 
 68-01 
 
 TiOa . 
 
 
 
 — 
 
 — 
 
 Tr. 
 
 AI2O3 
 
 
 i 14-08 
 
 13-62 
 
 13-78 
 
 17-34 
 
 PegOg 
 
 
 
 1-18 
 
 -70 
 
 1-07 
 
 3-66 
 
 FeO . 
 
 
 
 -85 
 
 — 
 
 — 
 
 — 
 
 MuO 
 
 
 
 
 Tr. 
 
 — 
 
 — 
 
 — 
 
 OaO 
 
 
 
 
 ■49 
 
 1-84 
 
 -12 
 
 2-06 
 
 MnO 
 
 
 
 
 -04 
 
 Tr. 
 
 -05 
 
 -77 
 
 K2O 
 
 
 
 
 5-39 
 
 4-39 
 
 3-27 
 
 4-41 
 
 NaoO 
 
 
 
 
 3-09 
 
 2-77 
 
 3-68 
 
 2-05 
 
 P2O5 
 
 
 
 
 •12 
 
 — 
 
 •17 
 
 •41 
 
 01 
 
 
 
 
 — 
 
 -06 
 
 — 
 
 -069 
 
 Loss on ignition 
 
 
 •34 
 
 1-21 
 
 -63 
 
 -64 
 
 Total . 
 
 100-33 
 
 99^92 
 
 100-01 
 
 100-249 
 
 I. Ben Rinnes Granite. II. Granite vein, Craigellaohie Bridge. III. Granite 
 vein, Fiddich Bridge. IV. Euthrie (grey) Granite, Aberlour. 
 
 *Flett, J. S. The Trap Dykes of the Orkneys. Trans. Roy. Soo.,Edin., Vol. xxxix. (1900). 
 
 fGoUer, Erw. Die Lampro^hyrKange des sudllchen Vorspessart. Neues Jahrbuch 
 fur Mineralogie, Beilage Band vi. (1889), p. 485. 
 
 X Mackie, W., M.A., M.D. Seventy Chemical Analyses of Rocks (chiefly from the 
 Moray area). Trans. Bdin. Geol. Soc, Vol. viii., Pt. i. (1901), p. 33. 
 
 On Differences of Composition between the Central and Marginal Portions of Granitic 
 Veins. Trans. Edin. Geol. Soc, Vol. viii. Pt. i., p. 98. 
 
44 
 
 EvplavMtion of Sheet 85. 
 
 
 V. 
 
 VI. 
 
 VII. 
 
 VIII. 
 
 SiOj . 
 
 58'44 
 
 53^22 
 
 5V78 
 
 54-09 
 
 TiO^ . . 
 
 
 Tr. 
 
 — 
 
 •80 
 
 — 
 
 AI2O3 
 
 
 21-43 
 
 16^84 
 
 19-74 
 
 16-72 
 
 Fe^Og 
 
 
 6-88 
 
 — 
 
 11-20 
 
 — 
 
 FeO . 
 
 
 ■31 
 
 9^27 
 
 — 
 
 9-38 
 
 MuO 
 
 
 
 Tr. 
 
 
 
 Tr. 
 
 -52 
 
 CaO 
 
 
 
 4-84 
 
 8^53 
 
 7-17 
 
 8-35 
 
 MgO 
 
 
 
 3-66 
 
 6^48 
 
 4-52 
 
 5-58 
 
 K2O 
 
 
 
 M4 
 
 r39 
 
 -99 
 
 •97 
 
 NagO 
 
 
 
 •59 
 
 3^54 
 
 1-76 
 
 1-23 
 
 1*205 
 
 
 
 ■23 
 
 — 
 
 -07 
 
 •39 
 
 CI 
 
 
 
 ■16 
 
 — 
 
 •18 
 
 •05 
 
 Loss on ignition 
 
 
 2^01 
 
 ■95 
 
 1-32 
 
 2^58 
 
 CO2 . 
 
 
 ■19 
 
 — 
 
 FeSj -54 
 
 — 
 
 Total . 
 
 99-88 
 
 100^22 
 
 100-07 
 
 99^86 
 
 V. Netherly Diorite — periphery of boss. -VI. Netherly Diorite — nearer centre. 
 VII. Netherly Diorite — centre of boss. VIII. Diorite, Dandaleith. 
 
 II. The Earlier (Foliated) Igneous Eocks. 
 
 The second group of igneous rocks represented in this area is 
 obviously prior to part at least of the earth movements which have 
 affected the region, and this is reflected in their structure. They 
 are more or less foliated and altered in their mineral constitution. 
 The acid rocks are now in the condition of augen gneisses, the basic 
 principally hornblendic schists. 
 
 Grey augen gneisses, which have apparently been developed from 
 porphyritic muscovite granites, occur in the immediate vicinity of 
 Keith, and also at localities some miles to the south and north of 
 it. Large elliptical phacoids of pearly white felspar, sometimes 
 showing Carlsbad twinning, lie in a finely gneissose matrix 
 consisting of muscovite, biotite, and granulitic quartz and felspar. 
 Cataclastic structures are very highly developed, the felspar 
 of the phacoids (which is in large part microcline) is much 
 broken and shattered and injected with veins of finely granulitic 
 material. 
 
 The basic foliated igneous masses belonging to this earlier series 
 are found principally in the south-east corner of the sheet, and are 
 well exposed in the sections on the Blackwater, a tributary of the 
 Deveron. They are gabbros, epidiorites, hornblende schists and 
 serpentines, but vary in character a good deal, some showing a 
 more complete reconstruction than others in which the original 
 structui'e of igneous rocks are still well preserved. 
 
 Among the less altered types may be instanced the gabbro, one 
 mile north of Blackwater Lodge, at the extreme south margin of 
 the sheet, which consists of brown, turbid schillerised diallage and 
 
Petrography of the Area. 45 
 
 basic plagioclcase felspar. Flaser structure is visible in the hand 
 specimen, as the rock is crossed by parallel streaks of dark green 
 hornblende. Under the microscope the structure is in places that 
 of a normal gabbro without olivine, but for the most part the 
 diallage is passing into a pale green amphibole which forms masses 
 of fibrous prisms, in the centre of which more or less of the original 
 pyroxene remains. This diallage is often broken, the felspar 
 shows a superinduced twinning due to pressure, and is becoming 
 granulitised. A dark brown original hornblende sometimes 
 surrounds the diallage, but the green amphibole is of new formation, 
 and may be seen to radiate outwards from the diallage, penetrating 
 the surrounding felspar. 
 
 A section of a specimen taken along the outcrop of this mass a 
 little further to the north shows that the schillerised diallage is 
 here changed entirely into green hornblende in large, compact 
 masses of irregular outlines, enclosing nixmerous grains of opaque 
 iron oxide. The felspars are coarsely granulitic, the original 
 structure of the gabbro being obliterated. In this felspar small 
 ragged prisms of hornblende lie scattered. There is a little biotite 
 and epidote, but no pronounced foliation or parallel structure. The 
 rock is an epidiorite. 
 
 Associated with this gabbro there is a mass of serpentine. In 
 section it has very much the appearance of having resulted 
 from the decomposition of pyroxene, as the rectangular lattice 
 structure is well marked. The original rock may have been a 
 pyroxenite. 
 
 At Craigdorney, further north-east along the same outcrop, there 
 is a diallage peridotite which presents some points of interest. The 
 rock consists principally of olivine and diallage, the former in 
 rounded masses weathering into yellow green sei-pentine which is 
 covered with a meshwork of dusty magnetite. The pyroxene is 
 almost colourless, with a perfect platy lamination and innumerable 
 minute dark enclosures which render it almost opaque, and are 
 disposed in at least two series. Occasionally a small mass of 
 diallage, with brown, platy schiller enclosures of the usual type, 
 forms a centre surrounded by the paler variety. There is no lustre 
 mottling or poikilitic structure, but the diallage is much broken 
 and bent. Tremolite is abundant in colourless prisms which 
 surround and penetrate the clusters of olivine grains, and pass in 
 winding streams through the broken plates of diallage. It is often 
 free from enclosures, or may be filled with dusty magnetite. 
 Evidently it has been developed at the expense of olivine, or 
 perhaps partly also from diallage. The rock contains no felspar. 
 A very pale yellow, almost colourless chlorite is a rather plentiful 
 ingredient of the rock, and appears to have resulted from the 
 weathering of the diallage.* 
 
 A somewhat more advanced stage of metamorphism has been 
 reached by the basic sills on the Blackwater, above Ardwell Bridge. 
 They are represented in the collection of slides by 1788 hornblende 
 
 * Patton, H. B. Serpentin und Amphibol Gesteine von Marienbad. Tsohermak's Min. 
 Petrog. Mittheil., Vo). ix. (1888), p. 111. 
 
46 Explanation of Sheet 85. 
 
 rock, schistose, with large porphyritic hornblendes ; 9548 and 
 9595, hornblende schists with a little epidote and decomposing 
 felspar. The last of these is fine-grained with drawn-out eyes of 
 hornblende resembling phenocrysts, and would seem to have been 
 originally an augite porphyrite. In these rocks no trace of original 
 igneous structures remains, with the exception of these indications 
 of porphyritic structure. 
 
 On the Blackwater, 300 yards above the bridge at Ardwell, there 
 is a hornblende schist filled with little oval lenticles of calcite, which 
 readily weather out, giving the rock a pumiceous appearance. The 
 calcite seems to have been present before the production of the 
 foliation, as around the spots of this mineral there is always a 
 border of hornblende and biotite which appear to be pushing in- 
 wards, penetrating the calcite, much as the hornblende in sheared 
 gabbros can be seen to spread through the felspar. The calcite 
 forms a mosaic of crystalline grains, with few traces of fracture or 
 deformation. The matrix of this schist consists of a foliated, fine- 
 grained aggregate of hornblende, biotite, and plagioclase felspar, with 
 much magnetite and finely granular epidote. It may have been a 
 fine-grained, vesicular, basic sUl, but the appearance of the 
 rock suggests at once the possibility that it is a contemporaneoiis 
 lava. 
 
 III. Metamorphic Eogks of Sedimentaky Origin. 
 
 Metamorphic rocks of sedimentary origin occupy by far the 
 largest portion of this sheet. In the north-west there is a large 
 area of quartzose and micaceous schists, with thin flaggy granulitic 
 gneisses (Moine schists). In these, though there can be no doubt 
 of their ultimate nature, all trace of clastic structures has disappeared. 
 An account of the microscopic characters of this group of rocks will be 
 found in the Explanation of Sheet 75, pp. 35 and 36. 
 
 At Ballindalloch a zoisite granulite forms a band in this series. 
 The rock is a fine-grained, granulitic gneiss, with a good deal of 
 biotite in small scales rather uniformly dispersed, so that the rock 
 is grey with paler and darker streaks. In this there is a light- 
 coloured band, with well marked lenticular folia of biotite. The 
 microscope shows that the principal components are quartz and 
 felspar in rounded or interlocking grains, mingled with small 
 irregular scales of biotite, which give it a parallel structure. The 
 felspar is partly untwinned orthoclase or albite, but includes also 
 a considerable amount of polysynthetic crystals, which sometimes 
 show two sets of intercrossing lamellse, and are partly oligoclase, 
 partly more basic varieties. Garnet is present in crystals up to 
 2 mm. across, and, in addition, zircon, apatite, epidote, zoisite, 
 magnetite, and a reddish, pleochroic sphene. 
 
 The zoisite is in lath-shaped crystals, which, while not highly 
 idiomorphic, often show bluntly-pointed terminations and angular 
 cross sections, which are bounded by crystalline faces. The crystals 
 
Petrography of the Area. 47 
 
 are from four to ten times as long as broad, have a perfect longi- 
 tudinal cleavage and numerous transverse fractures. In polarised 
 light they give the usual dark-blue colours, straight extinction, and 
 exhibit longitudinal stripes which recall polysynthetic tvrinning. A 
 pale yellow, almost colourless epidote is common also in small, 
 irregular grains, often surrounded by zoisite in parallel growth. The 
 zoisite crystals are small, ranging from '5 by "12 mm. down to 
 minute granules, the average diameter of the felspar and quartz 
 being -2 to '3 mm. In certain bands the zoisite is abundant, in 
 others scanty, and it is often to be remarked that intimately 
 associated with it there is a very small amount of calcite, which 
 elsewhere is practically absent from the rock. 
 
 Whether the zoisite is to be attributed to the effects of mechanical 
 shearing on basic plagioclase, or to the contact action of igneous 
 intrusive masses on a calcareous granulite, is not quite clear in this 
 case, as it will be seen that, from its proximity to the Ben Rinnes 
 granite, evidence might be adduced in support of either view. These 
 minerals are by no means common accessories in rocks of this group, 
 but they have been met with in Ross-shire and Inverness-shire 
 by Mr. Gunn, Mr. Home, and Mr. Grant Wilson, and described by 
 Mr. Teall in the Annual Reports for the years 1897 (p. 41), 1898 
 (p. 13), and 1899 (p. 40). As will be seen on reference to the 
 descriptions, there is a certain amount of similarity between the 
 specimens from widely separated localities. All are granulites con- 
 sisting of quartz, felspar, and biotite, with accessory garnet, sphene, 
 zircon, iron ores, rutile, epidote, and zoisite. But the prevalent 
 tjrpe in Inverness and Ross-shire contains hornblende, which is often 
 micropoikilitic with enclosures of quartz and felspar, a structure 
 also shown by the zoisite in some cases. Hornblende, however, is 
 absent from the zoisite granulite of Sgurr Mor Fannich (Annual 
 Report, 1898, p. 13). The Ballindalloch rock appears also to 
 be. a good deal finer grained than those previously described, 
 in which the zoisites are sometimes 7 to 8 mm. long. But 
 it is clear that as a group those zoisite granulites have a well- 
 defined character; and, indeed, the nature of this rock was 
 recognised by Mr. Hinxman from its appearance in the hand 
 specimen, though the zoisites are much too small to be visible to 
 the naked eye. 
 
 In the rocks of the Banfishire series, which occupy the eastern 
 half of this sheet, metamorphism is far less advanced than in the 
 western granulitic schists. The original clastic structures are often 
 to be traced, while in some cases they have suffered little modification. 
 Thus, in the sections on the Blackwater, in the extreme south-east 
 corner of the sheet, bands of grit or greywacke occur containing 
 rounded grains of quartz and of weathered felspar in a dark, fine- 
 grained matrix. There are practically no signs of mechanical strain 
 in the quartz with the exception of a lamellar structure visible 
 between crossed nicols as ill-defined, parallel bands. The matrix 
 consists of fine-grained quartz and brown biotite in small scales, 
 which, from their perfect freshness and the fact that they frequently 
 ■penetrate the quartz, are of new development. The crystalline 
 
48 Hxplanation of Sheet 85. 
 
 nature of the ground mass, in view of the absence of cataclastic 
 structures, may be reasonably ascribed to contact action by the 
 adjacent intrusive epidiorites. 
 
 The section of a qiiartzose grit from Drummuir shows an 
 essentially similar rock, in which somewhat greater modification has 
 taken place. Although quite a grit or greywacke in the hand 
 specimen, the rock shows under the microscope that the quartz 
 grains have been drawn out and fractured and wisps of a pale 
 mica have been developed, probably from an original felspathic 
 ingredient. 
 
 A still further stage of alteration is seen in sections prepared 
 from the gritty bands which occur among the phyllites in the 
 railway cutting at Mulben. In these, original clastic structures 
 can seldom be observed. A fine mosaic of granular quartz, crossed 
 by scales of biotite in parallel series, is the appearance usually 
 presented. The mica penetrates the quartz, passing through it 
 without regard for its boundaries . Reconstruction is fairly complete, 
 for it is rare to find that the quartz shows evidence of mechanical 
 strain or cataclastic fracture. 
 
 The silvery micaceous phyllites of this locality consist of muscovite 
 and biotite, intimately mixed, forming wavy parallel folia, often 
 crossed at high angles by an ausiveichungscUvage. Chlorite is 
 present, and rounded garnets which seem to be weathering into 
 chlorite. The other accessories are rutile, zircon, epidote, tour- 
 maline and magnetite. 
 
 The limestones of the Banfishire series have been converted 
 into granular, holocrystalline marbles, rather coarse-grained, and 
 often of a grey colour from the presence of disseminated graphitic 
 dust. They contain occasionally a few scales of a pale yellow, 
 slightly dichroic mica, which is more abundant in certain bands 
 where it is mixed with quartz to foiTa a sort of calc mica schist. 
 The mica may give the rock an ill-defined parallel structure. 
 Occasional rounded grains of quartz are the only common accessory. 
 There are, so far as the sections show, no calc-silicates, and their 
 absence may be due, as Mr. Grant Wilson suggests, to the original 
 purity of the limestone. 
 
 The black schist which is so characteristic a member of the 
 Banfishire series may be best described as a dark graphitic phyllite, 
 and in the hand specimen often shows the most minute puckering 
 and ausweichuTigsclivage. It consists of quartz, felspar, muscovite, 
 biotite, and fine graphitic dust ; and when coarser-grained passes 
 into a graphitic mica-schist. In addition to the usual accessories of 
 this group of rocks — magnetite, rutile, tourmaline, iron ores, pyrites, 
 and varying amounts of calcite, it contains often little clear, red, 
 rounded garnets, tremolite or actinolite, and chlorite. 
 
 The chlorite is practically an essential constituent, being always 
 present in the sections in greater or less amount. In colour, form, 
 and optical properties, it varies a good deal. It is commonly a pale 
 green or greyish-green mineral, with feeble dichroism, the rays 
 vibrating parallel to the cleavage being greyish green, perpendicular 
 to it slightly more yellow (pale yellow green). Pleochroic halos 
 
Petrography of the Area. 49 
 
 are frequent around small indeterminable enclosures. These are 
 black (very dark green) for the transverse rays {a and h). The 
 double refraction is much above that of ordinary chlorite, the 
 polarisation colours being grey of the first order, a little below that 
 of felspar. But the most noticeable peculiarity is the polysynthetic 
 twinning, seen between crossed nicols as light and dark alternating 
 stripes running parallel to the cleavage. The obliquity of extinction 
 in these twin lamellae ranges up to 12 degs. The mineral is always 
 optically positive, biaxial with a variable axial angle (up to about 
 40 degs.), and must be assigned to clinochlore. Its enclosures are 
 quartz, zircon, and fine dust of graphite or magnetite. 
 
 In this form it usually occurs in streaks, tufts or radiating 
 masses. There is no reason to believe that it is other than a 
 primary constituent of the rock, of which it forms distinct folia 
 alternating with others principally of qtiartz, or muscovite and 
 biotite (9596). In other sections (9597) from the black-schist 
 series, it forms little tablets with squarish or rectangular sections, 
 taking no part in the foliation of the rock, which they cross 
 obliquely; and it is usually associated with quartz in small, 
 rounded or lenticular spots. The polysynthetic twinning and 
 method of occurrence give it then a great resemblance to ottrelite, 
 from which, however, the lower double refraction and the hardness, 
 which is only about 2, serve best to distinguish it. This appears 
 to be the same mineral as is described by Mr. Teall (Mem., Sheet 75, 
 p. 11) as possibly chloritoid. 
 
 What appears to be another variety of chlorite, colourless, or 
 very pale yellow, is a very frequent constituent of the black- 
 schist, both in this sheet and in other parts of the Southern 
 Highlands. It shows the same polysynthetic twinning, oblique 
 extinction, optically positive character, and variable, mostly small, 
 axial angle. The pleochroism of the pale j^ellow crystals is slight 
 (c, pale yellow ; a and h, pale brownish yellow). A colourless 
 or pale yellow ottrelite has been described by Foullon* as a con- 
 stituent of certain graphitic calc mica schists, but that this is not 
 ottrelite is proved by its softness (H. = 2), flexibility, and low specific 
 gravity. By means of a borotungstate solution this was determined 
 to be 2'789 ; that of the clinochlore already described, 2'81. The 
 specific gravity of Foullon's material was over 3"15. As it is im- 
 possible to obtain flakes entirely free from enclosures, these figures 
 can be only approximations. In optical characters it resembles 
 to some extent margarite, a mineral recorded from corundum rocks 
 by WUliamst and Tschermak.t But of a large number of cleavage 
 flakes examined in convergent light, all were optically positive, 
 while margarite is negative. The double refraction is also too low 
 
 * PouUon, Baron von. Ueber die petrographische Besohaffeiiheit der Krystallinisohen 
 Sohiefer der unteroarboiiischen Schichten und einiger alterer Gesteine aus der Gegend 
 von Kaiserberg bei St. Michael ob Leoben. Jahrb. der k. k. Geol., Reiohsanst xxxiii., 
 p. 220 (1883). 
 
 f Williams, G. H. The Contact Metamorphism produced in the adjoining Mica Schist 
 and Limestones by the Massive Eocks of the Cortlandt Series. Amer. Jour. Sci. (1888), 
 Vol. 36, p. 254. 
 
 JTschermak, G. Ueber den Schmirgel von Naxos. Tsohermak's Min. Pett. Mittheil 
 Vol. xiv., p. 311 (1895). 
 D 
 
50 Tlxplanation of Sheet 85. 
 
 for a mica. In many cases in wliicli the two minerals could be 
 accurately compared in this respect, it proved to have always a 
 slightly lower double refraction than quartz ; though in vertical 
 sections it invariably gave higher colours than felspar, I'he 
 multiple twinning is usually obvious, thin plates, not more than 
 ■05 mm. thick, being sometimes composed of as many as ten 
 lamellae, but others are quite simple; and this explains the 
 irregular behaviour in convergent light. In hot, strong sulphuric 
 acid, the mineral was slowly attacked. These characters indicate 
 that it is a colourless chlorite with positive optical character and 
 oblique extinction, a member of the group of which leuchten- 
 bergite* is the best known example. It generally occurs in small, 
 well-formed plates which lie on the edges of small, rounded or 
 elliptical lenticles of quartz. The basal sections show rarely any 
 tendency to assume hexagonal outlines, but in the crushed powder 
 a parting along a six-rayed pressure figure is often visible, 
 vertical sections are rectangular or lath shaped. Not infrequently 
 it is in parallel growth with biotite, the two having their basal 
 planes in apposition. 
 
 A very frequent accessory in the black-schist is tremolite or 
 actinolite in elongated prisms, the, dark colour of which is due to 
 enclosed graphitic matter. In microscopic section, where free 
 from enclosures, the mineral is colourless or pale green. Long, 
 radiating prisms, arranged in feather-like aggregates, are some- 
 times visible on the surface of the hand specimens (9594, 2091). 
 That the crystals have been developed before the foliation of the 
 schist may sometimes be proved by their fractured condition, little 
 eyes of quartz having been formed in the wake of the broken 
 prisms (9595). In section 2091 the crystals of pale actinolite are 
 filled with dark graphitic matter in wavy parallel lines, and the 
 extinction sweeps over the section in undulations which correspond 
 to the puckering of the lines of enclosures. The crumpling of the 
 folia must be of later origin than the actinolite crystals. 
 
 From the abundance of tremolite in the calc-silicate hornf vises, 
 which alternate in thin bands with the black-schist, and the absence 
 or scarcity of carbonates in the black-schist itself when the amphi- 
 boles are present, it is probable that they are to be ascribed to the 
 action of contact metamorphism, whether by the earlier or later 
 intrusive igneous rocks, on the calcareous phyllites. The great 
 susceptibility of this series to contact alteration is one of its chief 
 characteristics, and has been noticed in the early chapters of this 
 memoir. 
 
 IV. Effects of Contact Metamorphism. 
 
 Effects of contact metamorphism are to be traced in many parts 
 of this area, and owing to the variety of rock types involved, a 
 considerable diversity of products is to be expected. Unfortunately 
 
 * Laoroix (Mineralogie de la France et de ses Colonies, T. i., p. 383) has found that 
 leuohtenbergite is common in the limestones of the Pyrenees where altered by contact 
 with ophites and Iherzolites. 
 
Petrography of the Area. 51 
 
 the exposures of the contact zone around the Ben Rinnes granite 
 are not good, but near Aberlour and Craigellachie the numerous 
 veins which intersect the schists have produced comparatively little 
 alteration. That is, perhaps, mostly due to the resistant nature of 
 these quartzose schists. The schist enclosures in the Ben Rinnes 
 granite (9605) and in the Netherly diorite are baked into a 
 compact biotite homfels ; while at Blue HUl, Aberlour, and at 
 Craigellachie, quartzo-felspathic-schists are indurated andhornfelsed. 
 Dr. Mackie records the presence of sillimanite in the masses 
 affected by the granite veins at the latter locality. In the igneous 
 rock itself flakes of biotite and hornfelsed leaflets of schist may be 
 traced along the margins of the veins, but there is nothing in the 
 way of endomorphic modification, except perhaps the presence of 
 small rounded garnets in the granitic rock. On Hunt Hill, north- 
 west of Aberlonr, the granite encloses numerous fragments of 
 quartzite and quartzo-felspathic-schists, the quartzites lustrous and 
 crystalline, while the felspathic quartzites have been to a large extent 
 re-crystallised, with the development of a mosaic structure (the 
 pjlaster-structur — " pavement structure " — of Salomon*). 
 
 At Netherly, on the Burn of Rothes, beside the little wooden 
 footbridge, there is the best exposure of the inner contact zone of 
 the newer granito-dioritic masses to be seen anywhere in this district. 
 The dark coloured, rather coarse-grained diorite is in the form of a 
 sill resting on and partly breaking across the quartzose schists. At 
 several places the actual contact can be inspected. Here, as every- 
 where in this sheet, these schists vary in character, certain bands 
 being mainly quartzose and felspathic, others richer in muscovite 
 and biotite. The more quartzose become converted into grey, 
 lustrous quartzites, which have a smooth, shining fracture. The 
 more felspathic and micaceous rocks have yielded biotite hornfelses, 
 consisting of quartz, felspar, and a rich brown biotite such as is 
 found in many contact zones. These rocks have lost their schistose 
 structure more or less completely, and may become spotted by the 
 development of biotite in nodular patches. Under the microscope 
 they consist of a mosaic of equidimensional grains (Salomon's 
 pavement structure) but the large conspicuous biotites are poikilitic 
 with enclosures, principally of quartz and felspar. 
 
 This type of structure, the spongy contact structure of Salomon,* 
 is still better seen in the andalusite and cordierite hornfelses 
 which alternate with those described. They are dark bluish or 
 grey rocks, turning brown when weathered, in which the schistose 
 structure has nearly entirely disappeared, while the development of 
 biotite in rounded areas gives them a dark spotted appearance. 
 Occasionally a pink band is produced by the presence of garnet. 
 
 Under the microscope they prove to consist of essentially the 
 same minerals as the cordierite rocks described by Mr. Teall from 
 the area to the south of this (sheet 75) and from around the Ben 
 Cruachan granite.t Quartz, orthoclase, and plagioclase felspars, 
 
 * Salomon, W. Ueber einige Binsohliisse metamorpher Gesteine im Tonalit. Neues 
 Jahrbuch fur Mineralogie, vii. Beilage Band (1891), pp. 482, 483. 
 t Summary of Progress of the Geological Survey of the United Kingdom for 1898, p. 88. 
 
^2 Explanation of Sheet 85. 
 
 deep brown biotite, muscovite, cordierite, andalusite, and garnet 
 are the principal ingredients. Zircon, rutile, sagenite in minute 
 networks, a green spinel, sillimanite, and iron oxides are the 
 commonest accessories. The more important minerals are not 
 irregularly scattered through the rock, but are distributed in bands, 
 in each of which one of them predominates, while from the others 
 it may be completely absent. Thus, certain bands are rich in 
 biotite and muscovite, others in quartz and felspar, others in 
 andalusite or garnet or cordierite, the contact minerals of new 
 development being confined to those parts of the rock which had 
 originally the composition necessary for their production. This 
 confirms the view taken by Mr. Teall and by Salomon* that the 
 formation of cordierite contact rocks around a granitic intrusion is 
 
 Fig 2. Graphic intergrowth of Quartz and Cordierite (shaded) as seen between 
 crossed Nicols. Cordierite Hornfels ; Netherly, Burn of Rothes Elein 
 (Section No. 9599. ) ' ^ ' 
 
 conditioned by the presence of certain types of schists. The primary 
 foliation thus indicated, is obscured by the new development of 
 poikilitic (spongy) structure, in which the contact minerals form 
 large plates of quite irregular form, as seen in section, filled with 
 enclosures of the other components. In this way occur garnet 
 biotite, cordierite, and andalusite, and to a less extent muscovite 
 and felspar. The commonest enclosures are quartz, felspar, zircon 
 iron oxides and biotite. The cordierite in one section (9659) is in 
 graphic intergrowth with the quartz it envelops ; the two minerals 
 
 * Salomon, W. Geologische und Petrographische Studien am Monte Aviolo in 
 Italienisohen Ant eil dev AdameUogrnppe. Zeits. dor deutschen Geol. GeseU R io 
 (1890) p. 504. ■' ■ 
 
Tetrography of tlie Area. 53 
 
 through interpenetrating one another have each a single position of 
 extinction over a considerable area (see Fig. 2).* Mr. Kynaston has 
 described a similar graphic intergrowth of quartz and felspar in the 
 Cheviot andesites as a product of contact alteration. t This points 
 to the mass having been at one time in a plastic or semifused 
 condition. It should be noted that Salomont has described glass 
 enclosures as present in certain contact minerals. At the same 
 time, the preservatioti of the original foliation, as described above, 
 shows that there was never sufficient liquidity to allow of mixing 
 taking place to any considerable extent. As Mr. Teall remarks, "the 
 cordierite contact rocks have certainly never been in a state of 
 igneous fusion ; and yet there has been a sufficient amount of 
 molecular freedom to admit of groupings of the same type as those 
 occurring in molten magmas."§ 
 
 The minerals of those rocks call for little remark. The cordierite 
 is colourless and not dichroic, except that it shows the usual halos 
 around zircon. It is not filled with streams of sillimanite needles 
 as in the rock of the Black Dog. II Sillimanite is, in fact, not easily 
 identified with certainty. Scattered yellowish prisms are abundant 
 in the rock, and may, perhaps, belong to this mineral, but the 
 characteristic divergent aggregates are much less common, though 
 also present. The andalusite is in spongy masses, or streams of 
 little rectangular prisms, colourless, or turning faint pink when the 
 polariser is rotated. The biotite is deep reddish brown, the garnet 
 pale red, and always poikilitic. Rutile occurs in prisms, in net- 
 works (sagenite), and intergrown in iron oxides in elongated 
 yellow prisms in the manner described by HutchingsIT in the ottrelite 
 slate of Tintagel in Cornwall. Quartz and felspar fomi a mosaic of 
 rounded, closely-fitting grains. The green spinel which is charac- 
 teristic of the cordierite contact rocks, is present in small rounded 
 octahedra, but is not abundant. The cordierite is mostly very 
 fresh, but in some of the slides it is weathering into a micaceous 
 mineral, and this facilitates its identification. 
 
 The black-schists and phyllites-of tlie Banfishire series in many 
 localities furnish minerals which may be regarded as contact 
 products. The tremolite and actinolite they frequently contain 
 have already been discussed in this connection. In the neighbour- 
 hood of Ardwell Inn, on the Deveron, chiastolite slates and stauro- 
 lite and andalusite schists are found in some places in contact with 
 the intrusive epidiorites and other rocks of the earlier igneous 
 series, in such a way as to leave no room for doubt that these 
 
 * Laoroix (Mineralogie de la France et de ses Colonies, T. i., p. 621) has recorded the 
 presence of quartz and cordierite in graphic intergrowth in certain rocks from the 
 Pyrenees. 
 
 «t.Kynaston, H. Notes on Contact Metamorphism around the Cheviot Granite. Trans. 
 Edin. Geol. Soc, Vol. viii., Pt. i. (1901), p. 24. 
 
 J Salomon, W. Ueber einige Einschliisse metamorpher Gesteine ira Tonalit. Neues 
 Jahrlmch fnr Mineralogie, vii, Beilage Band (1891), pp. 482, 483. 
 
 § Teall, J. J. H. On the Natural History of Cordierite and its Associates. Proc. 
 Geol. Assoc, Vol. xvi., Pt. 2, p. 72 (1899). 
 
 II Bonney, T. G., on Bastite-Serpentine and Trootolite in Aberdeenshire, with a Note 
 on the rook of the Black Dog. Geological Magazine, 1885, p. 439. 
 
 f Hutchings, W. Maynard. On the Occurrence of Ottrelite in the Phyllites of North 
 Cornwall. Geol. Mag. (Ill), Vol. vi., p. 214 (1889). 
 
54 Uxplanation of Sheet 85. 
 
 minerals are the result of their contact action. Section 9599, 
 andalusite and staurolite schist, from contact with the serpentine 
 on the Blackwater, shows a mica-schist, with muscovite and biotite, 
 large cross twins of staurolite up to ^-inch in length, filled with 
 enclosures of quartz, and crystals of pale, slightly pleochroic 
 andalusite, less numerous, with the same spongy structure. It is 
 to be remarked that the micaceous folia of the rock wind round 
 the staurolites and do not pass through them, a fact which suggests 
 that this mineral was of prior development to the foliation. Some 
 of the staurolites appear broken and shifted, while granulitic quartz 
 has penetrated between the fragments. But the shearing effects 
 of the folding in this region are local and variable, as may be 
 appreciated from the descriptions of the gabbro and epidiorite 
 masses, some of which are highly foliated, others almost massive, 
 or showing only the earlier flaser structures. The grit on the 
 Blackwater, which has already been mentioned, is free from 
 cataclastic structures, and another rock in the same condition is a 
 fine chiastolite slate, which is worthy of a rather more detailed 
 description. It was found on the hill immediately behind the 
 inn at Ar dwell. 
 
 The matrix of this slate (Fig. 3) consists of biotite in small, deep 
 brown flakes, finely divided quartz, and minute dark grains of mag- 
 netite and graphite. It is in that condition generally associated with 
 a fairly advanced thermal alteration, being much coarser-grained 
 and more crystalline than is normal in slaty rocks. An incipient 
 foliation is produced by the parallel disposition of the scales of 
 mica, and by their aggregation into winding parallel bands, which 
 curve round the chiastolite crystals. The rock is spotted, there 
 being paler rounded patches, in which, on the whole, mica is less 
 abundant and the structure more coarsely crystalline. Other 
 spots are due to little rounded nests of biotite and muscovite, and 
 in the centre of these sometimes a small chiastolite is foi'ming. 
 From place to place this matrix varies a good deal in character, 
 both in coarseness of grain and in the relative proportion of its 
 constituents. Scattered through it are small, rounded, almost 
 colourless garnets, and these are sometimes enclosed in the chias- 
 tolite crystals. 
 
 The crystals of chiastolite in transverse section are cross-shaped, 
 and consist of two arms crossing nearly at right angles. This is 
 due to the imperfect development of the edges of the prism, which 
 are represented by lacunae bounded by prism faces. In some 
 crystals the notches in the comer are deep, in others quite shallow 
 (see Fig. 3). The re-entrant angles are not due to twinning, as 
 the sections have a uniform extinction throughout. In the centre 
 of these crystals there is a dark core such as is usual in chiastolite, 
 lozenge-shaped in section, the edges being parallel to the faces of the 
 prism. It consists of chiastolite, enclosing fine graphitic dust. 
 This material bears no resemblance to the matrix of the slate ; it is 
 finer grained, contains little biotite, and is suflBciently transparent 
 to give the optical characters of chiastolite. From the corners of 
 this core, narrow lines of similar character pass outwards to the 
 
Petrography of the Area. 
 
 55 
 
 notches in the corners of the prism, and in many crystals these 
 lacunae are being filled up with the same turbid chiastolite, only in 
 this there is more mica, and the size of the enclosures is greater, 
 corresponding with that of the materials of the matrix of the slate. 
 In this way the imperfect edges of the prism are being healed up 
 by a growth- of impure material. 
 
 Evidently the centres of the prism faces, as was pointed out by 
 Eohrbach in describing similar crystals in a rock from Venezuela,* 
 grow outwards more rapidly than do the edges, which are left 
 
 Fig. 3. 
 
 Chiastolite in Chiastiolite Slate ; Ardwell Inn, Binffshire, 
 (Section No. 9603.) 
 
 The crystals show the cross-shaped transverse section, with the imperfect corners 
 being filled in with impure material. The small round clear crystals are 
 garnet ; an irregular mass of quartz is partly enveloped in the chiastolilf 
 
 behind and form depressions. A pure chiastolite, almost entirely 
 free from enclosures, gathers on the centres of the faces ; the 
 re-entrant angles are filled up with impure material, Becke,t who 
 accepts Eohrbach's explanation, compares this method of growth with 
 that of the " hour-glass " augites, in which molecules of slightly 
 different optical properties group themselves on difierent faces of the 
 crystal. The chiastolite may be said to grow in skeleton form and 
 at a later period to have the interstices of the skeleton filled up. 
 That this is a feature of the whole life history of a crystal is shown 
 by the radiate spokes which pass outwards from the, centre to the 
 
 * Eohrbach, C. E. M. Ueber die Chiastolith genannte Varietat des Andalusit. Zeits. 
 der deut. Geol. Gesell, Vol. xxxix. (1887), p. 632. 
 
 fBeoke, P. Ueber Chiastolith. Tsohermak's Min. Pet. Mittheil, Vol. xiii. (1892), 
 p. 256. 
 
56 Explanation of Sheet 85. 
 
 depressions on the suiface. They are the persistent traces of the 
 notches in the corners of the prism. Becke regards the central 
 enclosure as the trace of the terminal faces of the crystal, on which 
 he supposes a turbid chiastolite also to be deposited. Were growth 
 to continue till the skeleton is completely filled up, each corner of 
 the prism would show a rectangular dark spot, like that in the 
 centre, and connected with it by narrow lines, and like it with 
 edges parallel to the surfaces of the crystal; and this type of 
 chiastolite is well known. To this variety of chiastolite Sederholm* 
 has given the name of Maltesite. 
 
 Other proofs of contact action by the intrusive sheets in this 
 vicinity, are the dark biotite hornfelses into which the impure 
 shales above Ardwell Bridge have been converted in immediate 
 contact with the epidiorites (hornblende schists). 
 
 The calcareous layers intercalated in the black-schists in several 
 iplaces have been altered to calc-silicate-hornfelses, which consist 
 mainly of tremolite or a pale actinolite, often dark with abundant 
 graphite. Sections were prepared from rocks of this group collected 
 at Dufitown and at Tullochallum, on the river Fiddich. They were 
 fine grained, and in addition to the minerals named, one section 
 showed calcite, a pale yellow biotite, epidote, zoisite, quartz (?), 
 and a colourless mineral which was sometimes polysynthetic, most 
 probably plagioclase felspar. That these are products of thermal 
 metamorphism there can be little doubt, though it may not be 
 possible to point to any igneous mass, whether of the older or of 
 the newer series of intrusions, as indisputably the cause. 
 
 Away from the immediate vicinity of any exposures of intrusive 
 rocks, minerals which are frequent products of thermal meta- 
 morphism occur in many localities scattered over this sheet. While 
 in some cases there may be doubt to what cause there presence is 
 to be ascribed, taken as a whole they indicate a widespread thermal 
 action in this area. It may be interesting to give a list of them 
 and the localities in which they are found. 
 
 Ktanite. — Corriehabbie,t Boharm,t Mulben.t Allt Beagt (Glen 
 Rinnes), -Burn of Aldernie,t Mortlach,t Botriphnie.t 
 
 Andalusite. — Mortlach, Glen Tervie, Shenwell on the Blackwater, 
 Netherly (Burn of Rothes), Botriphnie, Auchentool.t 
 
 CoRDiEEiTE. — Netherly (Burn of Rothes). 
 
 STAUROLriE. — Near Keith,t Burn of Boharm,t Burn of Aldernie, 
 Auchentool, Shenwell on the Blackwater. 
 
 Chiastolite. — Near Keith, Ardwell Inn. 
 
 SiLLiMANiTE. — Netherly, Craigellachie. 
 
 Zoisite. — Ballindalloch (in granulite), Tullochallum (calc-silicate 
 hornfels). 
 
 Tbemolite. — Tullochallum, Dufftown. 
 
 Geeen Spinell. — Netherly. 
 
 * Sederholm, J. G. Om Maltesit en Kiastolitartad andalusitvarietet frSn Bstra 
 Finland. Geol. Foren. Forhandl., No. 173, B. 18, p. 391, 1896. 
 \Spa Heddle's "Mineralogy of Scotland." 
 
Petrogra'pliy of tJiM Area. 
 
 57 
 
 Of the metamorpliic schists, and Banifshire Series also, we are 
 fortunate in possessing a number of recent chemical analyses, for 
 which we are again indebted to Dr. Mackie, of Elgin. The list 
 appended is extracted from his papers in the Transactions of the 
 Edinburgh Geological Society, Vol. viii., Pt. 1901, pp. 33 and 98. 
 
 
 I. 
 
 II. 
 
 III. 
 
 IV. 
 
 V. 
 
 VI. 
 
 VII. 
 
 SiOa 
 
 56-67 
 
 72-48 
 
 77-37 
 
 54-01 
 
 75-10 
 
 96^51 
 
 72^64 
 
 TiO^ . 
 
 1-45 
 
 — 
 
 — 
 
 -89 
 
 — 
 
 . _ 
 
 1-4:2 
 
 AI2O3 . 
 
 20-25 
 
 15-86 
 
 11-22 
 
 22-86 
 
 14-23 
 
 2^02 
 
 1V61 
 
 FeaOg . 
 
 7-01 
 
 3-25 
 
 2-92 
 
 — 
 
 3-99 
 
 ■77 
 
 ' 4^86 
 
 FeO 
 
 — 
 
 — 
 
 .— 
 
 7-33 
 
 — 
 
 
 
 — 
 
 MuO . 
 
 •64 
 
 — 
 
 — 
 
 Tr. 
 
 — 
 
 
 
 ■46 
 
 CaO 
 
 5-04 
 
 2-21 
 
 1-40 
 
 1-11 
 
 ■74 
 
 ■26 
 
 1^20 
 
 MgO . 
 
 1-52 
 
 -12 
 
 -46 
 
 1-91 
 
 1-08 
 
 ■05 
 
 ■98 
 
 K,0 . 
 
 2-54 
 
 2-51 
 
 2-94 
 
 5-12 
 
 1-64 
 
 ■25 
 
 2-07 
 
 Na^O . 
 
 3-58 
 
 3-18 
 
 2-31 
 
 2-71 
 
 1-74 
 
 ■07 
 
 2-93 
 
 P2O5 . 
 
 -09 
 
 — 
 
 — 
 
 -20 
 
 Ti-. 
 
 — 
 
 ■22 
 
 01 . 
 
 ■025 
 
 — 
 
 — 
 
 — 
 
 
 
 — 
 
 ■010 
 
 Loss on 
 
 
 
 
 
 
 
 
 ignition 
 
 1-47 
 
 •53 
 
 -95 
 
 3-98 
 
 1-62 
 
 ■46 
 
 1^35 
 
 Total . 
 
 100-285 
 
 100-14 
 
 99-57 
 
 100-12 
 
 100^14 
 
 100^39 
 
 99-75 
 
 I. Dark Mica-Schist, Rothes Burn. II. Dark Mica-Schist, same 
 locality. III. Quartz Mica-Schist, Rothes Burn. IV. Schist under 
 Granite Vein, Oraigellachie Bridge. V. Another specimen, same 
 locality. VI. Quartzite, "West of Rothes. VII. Dark Micaceous 
 Slate, Mulben, Banffshire. 
 
 J. S. F. 
 
58 Explanution of Sheet 85. 
 
 CHAPTER VIII. 
 OLB BED SANDSTONE. 
 
 The Old Red Sandstone in this sheet covers an area of about 36 
 square miles along the northern margin of the map. The strata 
 belong to two divisions of that system — Orcadian and Upper — 
 neither of which is typically developed within the limits of the 
 sheet. They are separated from each other by an unconformability, 
 for the members of the Upper Old Eed Sandstone not only rest on 
 the basal conglomerates of the Orcadian Series, but pass on to the 
 crystalline schists. 
 
 The recent additions to our knowledge of the fossil fishes and 
 plants of the Old Red Sandstone of Scotland, together with the 
 evidence lately obtained regarding the relations of its component 
 members to the newer granite masses of the Highlands, have 
 tended to support the view advocated by Murchison of a three-fold 
 classification of that system into lower, middle, and upper divisions. 
 The evidence based on the fishes and plants has been reviewed by 
 Dr. Traquair and Mr. Kidston respectively, and their statements 
 will be found in the palseontological part of the Appendix to this 
 memoir. In the course of the Geological Survey of Argyllshire, 
 evidence has been recently'got to prove that the lavas and breccias 
 in the Black Mount and Royal Forests, associated there with shales 
 yielding Psilophyton and therefore on the horizon of the Lower Old 
 Red Sandstone volcanic series of Lome, have been altered by the 
 intrusion of granite which is a continuation of the Ben Cruachan 
 mass. On the north side of the Grampians, however, pebbles 
 derived from the newer granite masses and their apophyses are 
 found in the basal conglomerates of the Orcadian series. The 
 latter series seems therefore to be of younger date than the lower 
 division south of the Grampians. J. H. 
 
 The Orcadian Series. 
 
 The whole of the Old Red conglomerate between the river Lossie 
 and Gallows Hill, forms part of the Middle or Orcadian series. In 
 the sheet to the north (95) this conglomerate dips towards the north 
 and underlies the fish-beds in the burn of Tynet. These beds contain 
 a fish-fauna similar to that of Achanarras (Dr. Traquair), and they 
 are found to the south-west of Tynet in the face of a rock escarp- 
 ment of one of the higher river terraces situated on the west side of 
 the Spey (95), 650 yards to the north of Dipple. 
 
Old Bed Sandstone. 59 
 
 The " Orcadian Series " in this sheet is composed almost entirely 
 of thick, coarse conglomerates. The beds that form the Old Red 
 Sandstone area, which extends from the river Lossie to some miles 
 to the east of the river Spey, afford unmistakeable evidence that at 
 the time when they were laid down the existing coast-line was 
 sinking at a rate corresponding to that of deposition. On the 
 east side of the river Spey, from Braes Cairn to near Boat-of-Bridge, 
 an unconformable junction separates the Old Eed Sandstone from 
 the Highland metamorphic rocks, and the successive beds which 
 compose the newer formation abut in turn against the underlying 
 quartzites and phyllites. 
 
 The ground between Braes Cairn and the main road to Fochabers 
 and Keith is occupied by an area of soft brick-red sandstones with 
 a few thin bands of a fine pebbly conglomerate, both with a general 
 dip of 10° to the north. In a small hill-stream to the west of the 
 " Cairn," successive beds of sandstone are seen in turn resting un- 
 conformably on the upturned edges of the phyllites. Close to 
 Braewyner and to the west of Pathside, there are excellent 
 exposures of the unconformable junction of the Old Eed Sandstone. 
 At the latter spot, resting on phyllites, are red and grey sandstones 
 containing small brecciated fragments of the adjacent metamorphic 
 rocks, and these are, in turn, overlaid by bands of conglomerate 
 which form part of the basal conglomerate to the south. The 
 brecciated fragments in this sandstone are sharp and angular, and 
 exhibit no signs of having been subjected to the action of running 
 water, but appear to have fallen from the ancient sea-cliff, and to 
 have been enclosed in the sandy matrix m situ. 
 
 The ground to the north of Altash rises rapidly to form the 
 Whiteash Hill, which is entirely composed of the basal conglo- 
 merate, well seen in the burn of Fochabers and its tributaries. These 
 side streams, locally known as " Dramlachs," flow through very 
 deep and narrow rock gorges. These have been eroded in the 
 boulder clay and conglomerate, and are often over 100 feet in depth, 
 with almost perpendicular sides only a few feet apart at the bottom 
 of the gullies. The conglomerate is generally fine, of a red or 
 purplish colour, vdth coarse bands and false-bedded sandy partings. 
 These sandy beds show that the conglomerate is inclined to the 
 north and north-west with an average dip of 8°. The pebbles vary 
 in size from fine gravel up to fragments 3 inches in diameter. The 
 materials out of which it has been formed have been derived from 
 the denudation of the Highland metamorphic series. Pebbles of 
 quartzite compose about two-thirds of the constituents, together with 
 various varieties of mica-schist and gneiss and a few well-rounded 
 pebbles of granite. In addition to these, pebbles of porphyrite 
 frequently occur and appear to have formed part of a contempo- 
 raneous volcanic rock. They have generally a dark ground mass, 
 through which 'are scattered decomposed crystals of felspar. A 
 similar rock is seen in place in the Gollachy Burn, between Port- 
 Gordon and Buckie, in the sheet to the north. 
 
 In the burn which drains the south-west slopes of Scotch Hill, 
 and near Culfoldie, the pebbles are almost entirely composed of fine 
 
60 JExplanation of Sheet 85. 
 
 grey sandstone. Their presence seems to indicate that local 
 denudation of this formation had taken place somewhere within 
 the limits of the Moray Firth basin at the time of the formation of 
 the conglomerate. 
 
 For three miles to the south of the Keith road the boundary line of 
 the Old Eed Sandstone on the east side of the Spey is only an 
 approximate one, as the ground is partly covered by the large peat 
 moss of Douglassheil and other superficial accumulations. In the 
 Allt Tersie, just below Scotshill farmhouse, there is an excellent 
 exposure of the unconformable junction between the conglomerate 
 and the Mulben phyllites. The conglomerate is very coarse, and 
 for a distance of a hundred yards is seen to rest upon a very 
 irregular and uneven surface of phyllite-schist with quartzose bands. 
 Between this exposure and the foot of the burn, and also in the 
 Spey section at Boat-of-Bridge, both the schists and the quartzites 
 are stained red, indicating that the Old Eed Sandstone beds as 
 originally laid down, extended considerably farther to the south. 
 
 The boundary line of this formation crosses the Spey valley a 
 little to the north of Orton junction, then winds round the Gerrack 
 Moss, and turning to the south a little to the east of Findlay's Seat 
 descends into the valley of the Spey a short distance to the north of 
 the Greens of Rothes, where low clifls of conglomerate are seen in 
 close proximity to flaggy quartzites. This portion of the boundary 
 line is very indefinite, Findlay's Seat being thickly clad with drift 
 and timber. 
 
 In the Eed Burn, near Aultonside, the steep banks are composed 
 of red crumbling conglomerate, dipping N. 10 E., and in the upper 
 branches of this stream there are numerous exposures of deep red 
 and purple conglomerate with yellow sandy patches. Over the 
 district of the Tiendland no rock appears at the surface ; but farther 
 to the north-west, the stream which rises south of Humbrack gives 
 a very good section as far as Braehead. It shows a red and 
 mottled purple conglomerate in which the stones are well rounded, 
 and reach as much as a foot in diameter. 
 
 Between Rothes and Coleburns a powerful fault forms the south- 
 west boundary of the Old Red Sandstone formation. This disloca- 
 tion is never actually seen between these two points, but appears to 
 follow the west side of the Glen of Rothes. That such a fault must 
 exist is proved by the fact that the Old Red Sandstone beds in the 
 railway section below Littlehaugh are smashed and brecciated, and 
 often inclined at high angles to the north, while in their immediate 
 vicinity metamorphic schists are seen in a similar broken condi- 
 tion. At the foot of the glen a small stream that rises below the 
 farm of Smallburn affords a good section of the conglomerate. 
 The beds dip N. 8°, and appear to be intersected by 'several small 
 faults. The stones are mostly well rounded with a smooth surface, 
 are larger at the top of the section than at the bottom, and appear 
 to have been derived from the gneiss and quartzites of the adjacent 
 metamorphic rocks. 
 
 The upper portion of the Glen of Rothes is very flat, and is 
 covered with alluvium and peat, but on its steep eastern slopes 
 
Old Red Sandstone. 61 
 
 between Bivchfield and Coleburns there are numerous rock exposures 
 showing bands of purple and red conglomerate, which are either 
 lying flat or gently inclined to the north. The fault which traverses 
 the Glen of Rothes must either die out or pass into the Old Red 
 Sandstone to the north of Coleburns. If this fault continues to 
 the north it must, in all probability, form the boundary line 
 between the upper and middle divisions between Gockmuir and 
 Culbackhillock, but there is no evidence on the ground in support 
 of this view. 
 
 Between Coleburns and Gedloch the conglomerate now occupies 
 an area which may have formed a small bay in the coast-line during 
 this period of deposition. On the south-side of the hollow, locally 
 known as the " Slogg," below Gedloch, steep cliflfs of a remark- 
 ably hard compact conglomerate, with a basal breccia, are 
 opposed to equally steep cliffs of metamorphic rock. From this 
 point to the river Lossie the Old Red Sandstone occupies the lower 
 slopes by Wardend and Shougle. At the foot of the Gedloch Burn 
 red and mottled conglomerate and banded breccia, with thin partings 
 of red sandstone, are seen resting unconformably on hard pink 
 quartzites. That the rock in the district around Thomshill is Old 
 Red conglomerate is inferred from the contents of the drift and the 
 presence of numerous conglomerate boulders which are scattered 
 over the surface, and also the exposure of a small patch of 
 conglomerate to the south of Thomshill. At the foot of the steep 
 slope which lies between the Hillhead wood and the river Lossie 
 there are several good rock exposures, exhibiting deep-red and 
 purple conglomerate, varying from fine to coarse, with well-rounded 
 stones. 
 
 Odtliees of Orcadian Series. — In this sheet the " Orcadian " 
 division of the Old Red Sandstone when it was first deposited, 
 must have extended very much further to the south than its present 
 limits. This is proved by the numerous outliers which are found 
 scattered all over the map, from the vicinity of the river Lossie to 
 the Lower Cabrach. 
 
 Between the river Lossie and the head of Glen Rothes there are 
 two areas of conglomerate and breccia around Middleton and Hang- 
 ingfold. That the conglomerate at these two localities had at one 
 time been continuous with the main body to the north, is proved by 
 the reddening of the intervening rocks. 
 
 On the east side of the Spey four outliers of the " Orcadian " 
 series have been mapped. The largest one is situated to the south 
 of the HUl of Towie, in a flat-bottomed, wooded valley, through 
 which flows one of the head tributaries of the river Isla. The 
 rock exposed along the bank of this stream is a deep-red fine con- 
 glomerate, with bands of gritty and pebbly sandstone. At Dufftown, 
 the western pier of the railway viaduct across the river Fiddich is 
 founded upon a coarse, red, brecciated conglomerate, and this small 
 area may extend a short distance up the valley towards Little Tulloch. 
 Near the railway summit between Dufftown and Drummuir there 
 is a patch of conglomerate too small to be shown on the one- 
 inch map. It is seen in the head of a small burn which runs down 
 from the Scant Hill and close to the railway. J. S. G. W. 
 
62 Explanation of Sheet 85. 
 
 In the extreme southern portion of the area under description, 
 two small outliers of the " Orcadian " or middle division of the Old 
 Red Sandstone rest unconformably upon the schists and quartzite 
 of the Banffshire series. 
 
 The more westerly of these is found immediately east of Craig- 
 head Inn, at the head of Glen Tervie, south of Ben Rinnes, and 
 occupies an area about a third of a mile in length along both sides 
 of the Tervie Burn. The rocks are exposed at several points along 
 the main stream and its tributaries, and consist of coarse, 
 tumultuously-arranged breccia or conglomerate, made up of large 
 sub-angnilar and rounded blocks of quartzite and mica-schist, the 
 former largely preponderating. The conglomerate closely resembles 
 that which occurs along the western and southern limits of the 
 Tomintoul outlier, with which this isolated patch was no doubt at 
 one time connected. 
 
 The extreme northern extremity of the Cabrach outlier, a 
 description of which will be found in the explanation of sheet 75, 
 also falls within the limits of this map, crossing its southern margin 
 a mile to the east of the river Deveron. The area is a very small 
 one, and the exposures of grey or red incoherent sandstone are 
 very scanty. The only point of interest is the. occurence of a bed 
 of contemporaneous lava, similar to that which is associated with 
 the Quarry Hill Sandstone near Rhynie, in Aberdeenshire. It is a 
 dark purple amygdaloidal rock, that may be described as an altered 
 andesite. L. W. H. 
 
 Upper Old Red Sandstone. 
 
 This division, which is largely developed in the Elgin district to 
 the north, only occupies a few square miles in the map. In the 
 north-west corner of the sheet there is a narrow, irregularly-shaped 
 stripe of the upper beds. In an old quarry near Lochaber about 15 
 feet of reddish-brown, hard, thick-bedded sandstone has been wrought. 
 This sandstone contains fragments of quartzite and mica-schist 
 similar to those of the metamorphic series immediately to the 
 south. Wherever the rock is exposed, the presence of a conglomerate 
 breccia indicates deposition in a bay of the ancient coast-line 
 between Laurenceton and Drum. Prom this farm to the point 
 below Rafford where this formation passes out of the sheet, the 
 boundary line has been drawn along the foot of the hard feature 
 produced by the underlying metamorphic rocks. 
 
 To the south-east of TuUoch and near the Black Burn, the colour 
 of the drift and the presence of some blocks of red and grey sand- 
 stone suggested the possibility of a concealed outlier of Upper 
 Old Red Sandstone. In 1880 a small trial opening was made, and 
 the rock was reached at a depth of five feet, very much jointed and 
 somewhat broken. This sandstone is rather hard, coarse grained, 
 and varies in colour from grey to light pink. It contains a few 
 yellow clay galls, and the beds appear to be horizontal. 
 
 A considerable area of these upper strata is found in the valley of 
 the Lossie between the Hills of Mulundy and The Wangle, and it is 
 
Old Red Soindstone. 63 
 
 very probable that the same beds lie beneath the large alluvial haugh 
 of Dallas between these two hills. In a small stream which flows 
 down the hillside above the Free Church of Dallas, there are several 
 exposures of decomposing conglomerate. A similar conglomerate 
 is to be seen in the river Lossie immediately below the village, and 
 red sandstone with green clay galls and conglomerate in the burn 
 at Auchness. The rock at each of these three localities in all proba- 
 bility represents the basal beds of the Upper Old Red Sandstone 
 series. In a quarry to the west of Dallas Lodge, white, yellow, 
 and reddish thick-bedded sandstones containing clay galls are seen 
 dipping to the north-west. In another quarry beside Hatton, the 
 face shows 40 feet of thick bedded yellow and white sandstone with 
 a gentle inclination to the west. Several miles lower down, on the 
 left side of the river Lossie, and at the edge of the stream alkivium 
 where it touches the SOO-feet contour line, there is a small patch 
 of sandstone about 12 feet in length, resting on quartisite. 
 
 To the north-east of Rosehill there is a small area of conglomerate 
 and sandstone. Theformer is extremely hard and very diiSerent from 
 the conglomerate of Glen Rothes and the Spey. It is composed of 
 sub-angular and rounded pieces of gneiss, quartzite and quartz. 
 The matrix is exceedingly hard, and in some places almost a 
 quartzite. On the south side of this conglomerate there is a small 
 patch of a fine white sandstone which contains fish-remains. 
 Although the actual junction between the conglomerate and the 
 sandstone is not exposed, the former is doubtless the basal portion 
 of the latter. 
 
 A narrow tongue of Upper Old Red Sandstone extends along the 
 north side of the Black Burn from Pluscarden Abbey to the northern 
 edge of this sheet. To the north of the Abbey the sandstones are 
 hard, coarse, and false-bedded, and contain pebbles of quartzite. The 
 quarry on the north side of the road near the bridge of Torrieston 
 has been opened in fine yellowish and white sandstones. These are 
 thick bedded, the yellow sandstone is very friable, and both present 
 a very marked diflerence to the hard quartzose sandstones found 
 higher up the hill and at the back of the Abbey. 
 
 Three hundred yards to the south of Westerton House, Black- 
 burn, a small patch of Old Red Sandstone is seen near hard, grey 
 metamorphic flags. To the east of Whitetree, in the same district, 
 there is a similar deposit, and in the absence of direct evidence to 
 the contrary these two small outliers are regarded as belonging to 
 the upper division of the Old Red Sandstone. 
 
 The triangular area of the upper beds indicated on the map to the 
 east of the river Lossie, and around Longmom Station, contains 
 the well-known fossiliferous locality of " Scaat Craig." In the centre 
 of the small glen through which flows the Longmorn Burn, and 366 
 yards to the south-west of Whitewreath, there rises a rounded knoll 
 of fine red and yellow crumbling conglomerate, locally known as the 
 " Scaat Craig." The bedding of the rock is quite distinct, and is 
 inclined at an angle of 8° in the direction of N. 20 W. The section 
 is now very much obscured by the crumbling nature of the rock, 
 the growth of plants along its face, and by rubbish shot over from 
 
64 Explanation of Sheet 85. 
 
 the cultivated ground above. Fossil fish-remains are got at the 
 " Craig," but they are not very numerous. They are most abundant 
 about 300 yards higher up in the bed of the stream and opposite to 
 the underway railway bridge, in a soft, yellow and red sandstone. 
 The fossils are very brittle and the greatest care is required to 
 presenre them, as they have often to be removed from the rock in 
 small fragments. Dr. Traquair has kindly supplied the following 
 list of fossils obtained from this svell-known locality : — 
 
 Psanimosteus pustulatus. Traquair. 
 Cosmacanthus Malcolmsoni. Agassiz. 
 Bothriolepis major. Agassiz. 
 Conchodus ostreiformis. M'Coy. 
 Holoptychius nobilissimus. Agassiz, 
 
 „ giganteus. Agassiz'. 
 
 ,, decoratus. Eichivald. 
 
 Polyplocodus sp. 
 
 For 200 yards to the south of the railway bridge, the beds are 
 inclined to N". 30 W. at a low angle. This section is composed of 
 bands of fine conglomerate, with coarse deep red, and light and dark 
 yellow sandstones. Some of the sandstones are ripple-marked, and 
 the contrasting colours of the difierent bands produce a very fine 
 efiect. At the end of this section there is a gap of about 200 yards 
 before the deep red conglomerate of the " Orcadian " group 
 appears. J. S. G. W. 
 
 Mr. Taylor, Lhanbryde, has furnished a note of the fossils 
 collected by him in recent years from the following localities in the 
 Upper Old Eed Sandstone : — (1) from quarry near Burgie House, in 
 the north-west corner of the sheet, Psammosteus Taylori, Bothriolepis' 
 major; (2) from Hatton Quaviy, near Dallas, Holoptychius nohilissimus; 
 (3) from Pluscarden Abbey Quarry, Holoptychius nobilissimus; (4) 
 Torrieston Quarry, about half-a-mile east of Pluscarden, Holoptychius 
 nobilissimus and Bothriolepis fragment. Mr. Taylor's determinations 
 have been confirmed by Dr. Traquair. 
 
 The horizons in the Upper Old Eed Sandstone to which these 
 fossils probably belong will be discussed in the memoir of the Elgin 
 district (sheet 95). J. H. 
 
Glacial Drift and Recent Deposits. 65 
 
 CHAPTEE IX. 
 
 GLACIAL DRIFT AND REGENT DEPOSITS. 
 
 Glacial Drifts. 
 
 During the period of maximum glaciation the region under 
 description appears to have been under the influence of two principal 
 ice-movements. The centre of dispersion in the one case lay to 
 the west and north-west, from which the ice moved south-eastwards 
 over the hilly country between the Lossie and the Spey. The 
 mountain ranges of Cairngorm and the Monadhliath in the south- 
 west formed another great centre, whence the ice-sheet descended 
 on to the plains of Moray. 
 
 Few striated or ice-worn surfaces are to be seen. In the western 
 portion of the area the rocks are mostly concealed beneath super- 
 ficial deposits, and where exposed are, from their nature and rapid 
 weathering, ill-adapted to retain ice-markings. Striae pointing 
 east and south-east are seen near Eafford, in the north-west corner 
 of the map, and seem to be due to the earlier glaciation ; but the 
 few other striae found along the courses of the Spey and Deveron 
 belong to the later valley glaciation, and follow the trend of the river 
 valleys. Such later ice-markings are seen at Carron (E. 20 N.), and 
 Tomhead near Arndilly (north-west) in Strathspey ; at Craigdorney 
 on the Deveron (north-east) ; and at Braehead, south of Keith 
 (N. 40 B.). The distribution of boulders and nature of the drift 
 would seem to indicate that the ice-sheets coming from the north 
 and south-west were confluent along the north side of the Spey 
 valley as far, perhaps, as Aberlour. To the north of that point the 
 Moray ice became dominant, causing a deflection of the Strathspey 
 ice-sheet to the east ; while the contents of the drift over the 
 ground north of a line drawn from Craigellachie to Keith show that 
 it was derived from areas lying to the west and north-west. 
 
 Erratic Blocks. — Boulders of a coarse pink granite with large 
 crystals of orthoclase, and also containing microcline, are found in 
 great numbers on the hill slopes and summits between Dallas and 
 the Spey, and extend eastward as far as the seaward slopes of the 
 Mannoch Hill. They have evidently been derived from a mass of 
 similar granite which covers a considerable area on the Findhorn 
 between Coulmony and Dulsie Bridge. The granite mass of Moy, 
 still further to the west, is the probable source of blocks of grey 
 biotite-granite which are scattered freely over the same region, and 
 have been traced south-eastwards beyond Knockando and Phones 
 in Strathspey. L. W. H. 
 
 E 
 
66 Explanation of Sheet 85. 
 
 Further confii-mation of the ice-carry from a centre of dispersion 
 lying J;o the north and north-west, is found in the blocks of con- 
 glomerate and sandstone distributed over the northern part of the 
 area. 
 
 Numerous large boulders of the peculiar conglomerate-breccia of 
 Stonewells, north-east of Elgin, are found considerably to the south- 
 east of that locality ; two erratic blocks — the one of deep red sand- 
 stone, the other yellow with green galls, both of which have been 
 derived from the upper Old Red Sandstone strata of the Firidhorn 
 valley — are seen at the Meikle Cairn, half-a-mile west of Breachry, 
 Dallas ; and similar evidence of the south-easterly movement is 
 afforded by the occurrence at Clackmarras and Fochabers Junction 
 of boulders of conglomerate, granite, and the blue cherty rock of 
 Stotfleld and Elgin. On the further side of the Spey, an easterly 
 carry along the northern margin of this area is indicated by the 
 presence, |-mile east of Mulben Station, of boulders of red sandstone 
 similar to that of Stotfield Links ; and of blocks of conglomerate 
 still further to the east in the direction of Keith. J. S. Gr. W. 
 
 Dr. Mackie, of Elgin, was the first to point out a local 
 dispersion of boulders of the Netherly diorite over the area 
 between the burn of Rothes and^ Ben Einnes.* Blocks of this 
 characteristic rock have been traced southwards across the Spey at 
 Wester Elchies as far as Tom-na-Bat and the slopes of Ben Rinnes. 
 These may have been dropped in their present position by a marginal 
 lobe of ice flowing from the large glacier to the north through the 
 hollow that lies to" the east of the Hunt Hill down to the Spey, 
 at a time when the lower ground had been left bare by the retreat 
 of the Strathspey glacier. 
 
 Boulder Clay. — This deposit is well developed over the greater 
 part of the area, and especially on the higher hill-slopes to the 
 north-west of the Spey valley, where the ravines cut by the head- 
 waters of the streams flowing into the Spey and Lossie show the 
 boulder clay to be of great tluckness. 
 
 It varies in character with the nature of the underlying rocks. 
 Over the area occupied by the quartz-schists and flagstones it is a 
 somewhat incoherent, yellow, sandy clay, but along the outcrop of 
 the black-schists and limestones it becomes dark in colour and 
 very argillaceous ; whUe over the areas occupied by the Old Red 
 Sandstone strata, and in the region lying immediately to the south 
 and south-east of them, it is red in colour and full of fragments 
 of these sedimentary rocks. Interstratified sands and gravels are 
 not common, but may be seen at Drumnagrain, one mile south- 
 south-east of Ballindalloch Station. The stones imbedded in the 
 boulder clay are mostly sub-angular blocks of local origin, but in 
 the western part of the area there are also many rounded boulders 
 of granite, probably derived from masses lying to the north and 
 north-west. 
 
 The present course of the Allt Arder, from the Bridge of Gaily 
 to its junction with the Spey, affords an interesting section of the 
 deposits filling up a pre-glacial valley. The stream is now flowing 
 * Trans. Edin. Geol. Soc, Vol. VIII. 
 

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Glacial Drift and Recent Deposits. 67 
 
 along the extreme northern side of the ancient valley, and has for 
 its left-hand bank the original rocky wall of the glen. The 
 southern or right-hand bank gives a clean-cut section of from 100 
 to 140 feet of fluvial and glacial deposits. The upper portion 
 consists of 20-35 feet of laminated sand and sandy clay, showing 
 oblique and current-bedding, and with occasional bands of pebbles 
 near the base. This is succeeded by 100-140 feet of sandy boulder- 
 clay, containing large angular blocks of quartzite and rounded 
 granite boulders. (Plate II.) L. W. H. 
 
 With the exception of a few bare hill-tops, the whole of the 
 ground to the west of the Spey and north of Knockando is covered 
 with superficial drift deposits. 
 
 Eed boulder-clay, largely made up of materials derived I'rom the 
 Old Eed Sandstone to the north-west, covers the slopes of the 
 Monaughty Hill. A portion of the Bildon Hill is clear of drift, but 
 the long ridge that lies between the Black Burn and the river 
 Lossie is again completely drift-covered. Thick deposits of 
 boulder-clay occupy the ground on the south side of this river. 
 The scars cut by the Lennox Burn show as much as 135 feet of 
 stony brown boulder-clay, sometimes slightly laminated, and near 
 the head of the burn from 20 to 60 feet of a greyish or yellow 
 clay is exposed. The Mannoch Hills are deeply swathed in 
 similar deposits, which to the west of this point seem to reach an 
 even greater thickness ; 100 feet of gravelly and sandy drift being 
 seen at the head of the Allt Arder, and nearly 200 feet at the Loch 
 of the Cowlatt. Numerous sections cut by the burn of Rothes 
 show that the yellowish-brown boulder-clay which fills the lower 
 part of the glen must have a thickness of at least 150 feet. 
 
 The right-hand bank of the river Spey, nearly opposite the village 
 of Rothes, is formed by a cliff, 200 feet in height, of boulder-clay 
 capped with sand and gravel. The lowest part of the section 
 displays a deep-red, very compact, boulder-clay, containing large 
 striated boulders. To this succeeds a considerable thickness of 
 compact greyish-brown clay with reddish patches and lenticular 
 bands of false-bedded sand and gravel. Mid-way up the cliff, and 
 apparently resting unconformably on this boulder-clay, there follows 
 a great thickness of regularly-bedded sand and gravel, forming part 
 of the high-level alluvial terrace which extends from near Aikenway 
 to the Wood of Arndilly. (Plate III.) 
 
 The distribution and character of the boulder-clay in the vicinity 
 of Rothes affords further evidence of the south-easterly movement 
 of the ice over this region. No red boulder-clay is found west of 
 the Glen of Rothes, and the reddened deposits only begin to appear 
 at various distances up to a mile to the east of the Old Red Sand- 
 stone boundary. The ground between the Wood of Dundurcas and 
 Findlay's Seat "is occupied by schistose rocks, but is covered with 
 compact red boulder-clay which must have come from the north- 
 west. Red boulder-clay is also spread over the low ground at the 
 foot of Ben Aigan, and is seen in the burn in Arndilly wood not far 
 fi-om the top of the hill. 
 
 The lower part of the Aultderg Burn, near Fochabers, affords a 
 
68 Explanation of Sheet 85. 
 
 very fine example of a pre-glacial valley in the course of being 
 re-excavated by the present stream. The phenomena of erosion 
 seen at this locality are very interesting, and are described later 
 on in this chapter. 
 
 The conglomerate area of the Scotch and Gallows Hills is mostly 
 covered with a gravelly drift deposit, but the south-easterly move- 
 ment of the ice has filled the valley of the Forgie Bum with deep-red 
 drift containing blocks of red sandstone identical with the rock 
 in place between Braes Cairn and Aulthash. A good drift section 
 is afforded by the burn to the north of Herrick's Moss, showing red 
 boulder-clay passing upwards into dark-brown clay capped with 
 sand and gravel. Another good section of compact redfish-brown 
 clay with polished and striated boulders is seen at Eosarie, 2^-miles 
 west of Keith. An analysis of the fragments contained in the clay 
 showed that 68 per cent, were quartzite ; 20 per cent, gneiss and 
 mica-schist ; 4 per cent, phyllites ; 4 per cent, granite ; and 4 per 
 cent. Old Eed Sandstone. 
 
 To the north-east of the granite area of Ben Einnes the drift is 
 largely composed of granite waste, while to the south of Keith the 
 country is covered with a stiff dark-grey and brown boulder-clay ; 
 facts which indicate that this part of the area lies outside the 
 influence of the Moray ice-sheet, and has been overspread with ice 
 coming from the south-west. The valleys between Dufftown, 
 Corsemaul, and the southern margin of the map are more or less 
 thickly covered with boulder-clay of a similar character, which 
 reaches a considerable depth in Glen Einnes, and at Lynemore 
 attains a thickness of 100 feet. Its local character varies with the 
 nature of the underlying rocks, but it is usually a dark stiff clay, 
 varying in colour between reddish-brown and grey. J. S. G. W. 
 
 Sands and Geavels. — A considerable extent of sands and 
 gravels of fluvio-glacial origin covers the low ground around Eafford 
 in the north-west of the map, and stretches southwards as far as 
 Bothies and Briach. These deposits are distributed over the area 
 either as flat plains of gravel, or in the form of small kamiform 
 ridges and hillocks. In the Granary Burn at Eafford the stratified 
 sands and gravels rest upon reddish-brown boulder-clay. On the 
 north side of the Hill of Mulundy the gravels merge into a series of 
 high-level terraces on both sides of the valley of the Blackburn. 
 These terraces are carved out of the boulder-clay slopes, and are 
 in some cases covered with sand and shingle. They are somewhat 
 irregular in disposition and extent; the longest have a gentle 
 inclination to the west contrary to the fall of the present river- 
 valley, and the highest of them reaches an elevation of a little 
 above 500 feet. A similar series of terraces is seen on both sides 
 of the river Lossie for two miles to the south of Dallas, the highest 
 of which almost reaches 800 feet, while the general inclination is in 
 this case down the valley. 
 
 A large area immediately to the south is occupied by sand and 
 gravel deposits, kamiform or possibly morainic in character, that lie 
 thickly around the Moss of Bednawinny, and extend to the head of 
 Glen Lossie, sweeping over the moorlands to the north-west as far 
 
6q 
 
Qlacial Drift and Recent Deposits. 69 
 
 as Eochuln. The stream in Glen Lossie has cut deeply into these 
 mounds at several points, showing the thickness of the deposit of 
 well-rolled fragments to Ise at least 100 feet. A soar, 200 feet high 
 on the hillside, a short distance east of the Loch of Dallas, shows 
 morainic drift resting upon thick sand, and the alluvial flat to the 
 north of the same loch is overlooked by morainic moiinds at least 
 200 feet in height. A few scattered gravel mounds are also 
 grouped round the farm of Whiterashes in the valley of the Burn 
 of Oorrhatnich. 
 
 The alluvial flat referred to in the last paragraph is locally known 
 as Loch-na-Braan, and marks the site of a loch which has been 
 drained by the lowering of the drift barrier at its eastern extremity. 
 The thick alluvial deposits laid down in this loch by the hill burns 
 have subsequently been denuded by the stream which now flows 
 through the flat, and has cut three distinct terraces out of the fine 
 sandy silt that fills the hollow. 
 
 A large number of sloping broken terraces, with surfaces covered 
 with false-bedded sand and gravel, are carved out of the red stony 
 boulder-clay which clothes the sides of the valley of the Blackburn 
 above and below Westerton House. As far as Crossley they have a 
 gentle inclination down the valley, but below this point they merge 
 into a broad flat plain of sand and shingle, which stretches east- 
 wards to the Lossie. Between the Kellas in Glen Lossie and the 
 hill-slopes to the east of the head of Glen Eothes, there is a further 
 development of these denuded sand and gravel terraces resting 
 upon boulder-clay. To the north they pass into a series of hillocks 
 of sand and shingle, which cover the ground between Paddock 
 Hall and Shougle and extend north-east as far as Blackhills House, 
 while similar deposits occupy the low ground round Orbliston 
 Junction, reaching as far south as Inchberry. A well-marked 
 flat terrace extends for about a mile along the western slope of the 
 Glen of Eothes just below the 600-foot contour-line, between the 
 Glen Burn and Birchfield. It has been cut out of the bouldei'-clay, 
 and is covered with sand and shingle. There are several other 
 terraces at lower elevations around the village of Eothes which 
 are probably more truly fluvial in their origin, and have to do 
 with an earlier phase in the history of the river Spey, 
 
 J.S. G. W.; L. W.H. 
 
 In the Glen of Mulben there is another large accumulation of 
 fluvio-glacial sand with bands of gravel, which frequently attains a 
 thickness of at least 100 feet. On the south side of the glen it 
 forms a well-inarked terrace, which extends from Sherifi'haugh to 
 Mulben Station, and has a general inclination of 1 in 150 towards 
 the river Spey. The same terrace can be traced, in a denuded and 
 fragmentary form, along the eastern side of the Spey valley under 
 the woods of Ordiequish and Slorach as far as the mouth of the 
 Fochabers Burn. 
 
 In the deep ravine at the foot of the Aultderg Burn, which falls 
 into the Spey above Burnside of Dipple, gravel rests upon boulder- 
 clay, which in turns covers the conglomerate below. The height 
 of the bank of the ravine below the farmhouse of Aultderg is exactly 
 
70 IBiffplanatio7i of Sheet 85. 
 
 100 feet, made up of nearly equal thicknesses of gravel, boulder- 
 clay, and conglomerate. The surface water rushing down the steep 
 slope of the Ordiequish Hill pours over the edge of the ravine, and 
 has carved out of these soft and incoherent materials a remarkable 
 assemblage of circular steep-sided pinnacles or earth pillars. 
 (Plate I., Frontispiece.) These pillars are invariably capped with 
 a thick covering of tough heathery herbage, and it is to this turf 
 capping that their origin and subsequent preservation is due. 
 The herbage on the slope above the ravine is of unequal thickness, 
 and the surface water as it streams over the edge of the chasm flows 
 round the thicker tussocks and isolates them from the surrounding 
 turf The portions bared of their grassy covering are rapidly, 
 eroded, with the result that the protected portions finally stand 
 out as isolated pyramids, each with its capping of turf. These 
 pillars can be seen in every stage of detachment and isolation 
 from the bank behind, and in those where erosion has proceeded 
 furthest, the gravel and boulder-clay rest upon a base of con- 
 glomerate. The wind acting upon the upper sandy layers often 
 undermines the grassy cap until it falls, and the unprotected pillar 
 wastes rapidly away. J. S. G. W. 
 
 The laminated sands described as capping the boulder-clay in the 
 Allt Arder section, form part of a deposit of fluvio-glacial sands and 
 gravels that occur at several points along the valley of the Spey. 
 Above Blacksboat and Mains of Kirdells they cover a considerable 
 area on the hill side, presenting a rolling surface of alternate ridge 
 and hollow that merges along its lower margin into the higher 
 alluvial terraces of the Spey. Further traces of the terraced fluvio- 
 glacial deposits are seen along the valley of Knockando Burn 
 between Tomdow and Priestfield. The steep bank on the south 
 side of the stream immediately below Knockando Church, gives a 
 section of 75 feet of fine white sand. On the farther side of the 
 same bum, below the Cardow Schoolhouse, a wide and well-marked 
 terrace extends eastwards towards Knockando House. It is com- 
 posed mostly of finely laminated clayey sand resting upon boulder- 
 clay, and seems along its northern margin to mark the position of 
 a small glacial lake occupying a hollow in the drift. A section in a 
 roadside quarry near Oardow shows great disturbance in the beds of 
 fine sandy silt and clay. They are tilted up at high angles, some- 
 times nearly vertical, and often violently contorted. The longer 
 axes of the stones that are scattered through the sand are always 
 parallel to the bedding planes in whatever position these may be. 
 The phenomena suggest the action of masses of ice grounding in 
 shallow water. L. W. H. 
 
 Bkick-Clay. — At Oraigellachie Brickfield the clay at present 
 wrought is a light-brown, laminated, glacial silt, with horizontal 
 bedding, and contains thin layers of fine sand or very small gravel, 
 with occasional pebbles up to 2 inches in diameter. This deposit 
 of clay is about 18-20 feet thick. It marks the site of what was 
 once a glacial lochan, and occupies a shallow depression in the 
 drift, about half-a-mile in length. At one portion of the section, 
 false-bedded glacial silt, sand, and gravel are exposed, and these 
 seem to indicate the presence of floating ice. J. 8. G. W. 
 
Glacial Drift and Recent Deposits. 71 
 
 Moraines. — There are few localities in this region where any 
 regular assemblage of moraines such as mark the track of a local 
 glacier can be observed, though isolated morainic mounds of 
 gravelly drift, often stratified, are seen in various places along the 
 Spey valley. 
 
 Such mounds occur at Panmore and Groftindacker, a short 
 distance west and north-west of Ballindalloch, and on the hillside 
 above Culfoichmore, seven miles higher up the river ; while a con- 
 siderable area in the higher part of the valley of the Allt Breac, in 
 the south-west corner of the map, is covered with morainic drift 
 resting upon boulder-clay. The disposition of the well-formed 
 moraines throughout this hollow indicates a movement of the ice 
 from the north or north-west. 
 
 A small morainic mound, almost entirely made up of well- 
 rounded fragments of quartzite, schist, and granite, lies on the 
 water-parting of Creag-an-Tarmachain, between the Spey and the 
 Avon, at a height of 2100 feet. It is diflBcult to account for the 
 position of this moraine, but the materials may have been deposited 
 by infra-glacial water in a hollow of the ice-sheet that enveloped 
 the Cromdale Hills. 
 
 Traces of the local glaciation of the Oonval Hills are seen in the 
 corrie on the north side of the Little Conval, two miles west of 
 Dufitown, where a fine specimen of a terminal moraine crosses 
 the mouth of the corrie, and has been cut through in two places 
 by the small stream that has its source on the slope of the hill. 
 These sections enclose large blocks of the Conval granite, and a 
 mass of the same rock rests on the summit of the moraine at its 
 western end. There are further indications of smaller terminal 
 and lateral moraines, both above and below the large moraine 
 described above. L. W. H. 
 
 Recent Deposits. 
 
 Freshwater Alluvium. — The largest stretches of alluvium are 
 found along the courses of the Spey, the Lossie, and the Black Burn. 
 Below Pluscarden Abbey the Black Burn meanders through two 
 wide haughs of fine sandy alluvium that were at one time marshes, 
 but have been drained by diverting the stream for several miles 
 into a deep artificial channel. A considerable stretch of alluvium 
 is also found at Bethelem, to the south of Dallas, and is due to a 
 change in the course of the river Lossie, which at one time flowed 
 through the well-marked channel south of Ballachraggan, but now 
 passes to the north of that farm. The village of Dallas is situated 
 on the low delta laid down by the Lossie at the head of the lake 
 that once covered the Haugh of Dallas. This extensive alluvial 
 flat is formed of fine sand and shingle ; a portion of it is cultivated, 
 the rest being covered with peat. In the region around Kellas, 
 the Lossie has eroded the thick glacial deposits that fill this river 
 basin, producing a fine series of terraces. These terraces lie below 
 those of fluvio-glacial origin, the highest of them being 62 feet 
 above the present level of the stream. J. S. G. W. 
 
72 Explanation of Sheet 86. 
 
 The alluvial terraces that show the successive levels of the flood- 
 plain of the Spey are well marked along the whole course of the 
 river through this sheet. 
 
 Between Ballindalloch and Oarron, as many as four, five, and six 
 of these terraces can often be distinguished on either side of the 
 river. The highest of these sometimes merges into, and is diffi- 
 cult to separate from, the fluvio-glacial deposits which in places 
 flank the sides of the valley — as between Blacksboat and Knockando. 
 The high-level terraces seen on either side of the Glen of 
 Eothes can be traced more or less continuously by Eothes and 
 Blackball into the Spey valley, and may be correlated with the 
 500-feet terraces at Phones and Culquoich, higher up ther river, 
 near Knockando. They indicate an earlier course of the Spey 
 through the Glen of Eothes, referred to in Chapter II. Similar 
 high-level alluvial deposits are continued up the valley of the 
 Avon, and are well seen between Ballindalloch and Drumin, where 
 the old castle stands upon a fragment of a higher terrace. 
 The materials at the lowest levels are coarse and often torrential 
 in character, but become finer upwards, and pass, in the highest 
 terraces, into fine sand and silt. This points to a progressive in- 
 crease in the gradient and consequent velocity of the stream as it 
 cut down through the deposit of an earlier waste-filled basin to 
 the rock fioor over which it is now flowing in this portion of its 
 course. L. W. H. 
 
 Between Dandaleith and Aikenway Castle there is a consider- 
 able stretch of flat alluvial land, the lower part of which is locally 
 known as the Haugh of Eothes. This alluvial stretch lies imme- 
 diately above the constriction of the valley at the Pass of Sourden, 
 and forms a basin that before the lowering of this rock-barrier may 
 have been occupied by the waters of a lake of considerable size. 
 Northwards from Boat of Bridge to the edge of the map, the 
 Spey has laid down a broad stretch of terraced alluvium — that 
 at Fochabers measures as much as 2| miles in extent from east to 
 west. A pit-section by the roadside ^ mile north of Inchberry, in 
 the highest but one of these river terraces, shows an alternating 
 series of fine and coarse gravels, fine sand, and clay bands. 
 
 As the majority of the streams on the east side of the Spey run 
 through narrow valleys with a rapid fall, there are few extensive 
 alluvial deposits in this part of the area. A broad belt of peat- 
 covered alluvium extends between Mulben and Newmill. The 
 greater part of this area was in all probability laid down when the 
 bum of Auchlunkart fiowed eastwards into the Isla. It has since 
 been beheaded by the Mulben Burn, and its waters now flow west- 
 wards to the Spey. Narrow stretches of alluvium occupy the 
 bottom of the valleys of the Fiddich, Dullan Water, Deveron, and 
 Isla. J. S. G. W. 
 
 Peat. — ^Basin peat is very generally distributed all over the map, 
 and in the area between the Lossie and the Spey there are some 
 very large and deep peat-mosses. The largest moss of this area is 
 that of Bednawinny, near Dallas, which is about one square mile in 
 extent. In the past these mosses were the chief source of supply 
 
Glacial Drift and Itecent Deposits. 73 
 
 for the fuel used in the district, and they are now in many cases 
 extensively wrought to supply the local distilleries. At the Kettles 
 and the surrounding peat mosses large roots and stumps of Finns 
 Snotim," are found at the bottom of these bogs. The Douglasshiel 
 and Gow Moss supplies Keith with a portion of its fuel, and in 
 the Lower Cabrach the peat moss between Craigwatch and the 
 Brown Hill is very deep. 
 
 In addition to the basin peat, a large tract of country lying on 
 the watershed between the Spey and the Lossie is covered with hill 
 peat of varying thickness, and between Dufftown and the south- 
 east comer of the sheet a similar covering envelops the hill-tops 
 and ridges. J. S. G. W. 
 
 On the western slopes of Ben Kinnes and in Glen Tervie there 
 are several peat mosses, most of which are worked for fuel. None 
 of these is of very great extent ; the largest are found in the Drum 
 of Carron, on the eastern slope of Garnacay, and at the head of 
 Glen Tervie, near the farm of Tomachclaven. A large peat moss 
 appears along the western margin of the map at the foot of the 
 Larig Hill, and peat is also dug at various points along the valley 
 of the AUt Breac below Auchnagallin. 
 
 The probable exhaustion at no very distant date of the more 
 accessible areas of basin peat, renders the hill-peat, that covers such 
 wide areas in this region, of some economic importance, this fuel 
 being so largely used in the numerous distilleries of Banffshire and 
 Elgin. L. W. H. 
 
74 Explaimtion of Sheet 85. 
 
 CHAPTER X. 
 
 EGONOMIG PRODUCTS. 
 
 The principal rocks of economic value in the district are the 
 limestones of the Banffshire series. The two principal lime-works 
 in this portion of the county are situated at Blackhillock, near 
 Keith, and at Parkmore and Tininver, Dufftown. There are several 
 small openings in Morinsh and along the outcrop of the limestone 
 in Glen Einnes, also in Glen Piddich, Glenmarkie, Corsemaul, 
 Lower Towie, Douglasbrae, and Handslach. At Keith, operations 
 are carried on by the Blackhillock Lime Company, Limited, and 
 the annual output of lime is from six thousand to seven thousand 
 tons per annum. The limestone rock in the quarry is of a very 
 high quality, and a sample has been analysed by J. Falconer King, 
 City Analyst, Edinburgh, with the following results : — 
 
 Carbonate of lime 
 
 9670 
 
 Carbonate of magnesia 
 
 270 
 
 Sulphuric acid 
 
 traces 
 
 Iron oxide and alumina 
 
 0-15 
 
 "Water 
 
 0-20 
 
 Silica 
 
 0-68 
 
 100-43 
 
 The lime manufactured by this company is to a large extent used 
 for building and plastering work, while less than one-fourth of the 
 total annual output is utilised by the district farmers for agricultural 
 purposes. In addition to the local requirements, this company 
 supplies lime to the wide district between Keith, Inverness, and 
 Aberdeen, and it also consigns by rail to Wick, Thurso, Kyle of 
 Lochalsh and Ballater. 
 
 The Parkmore and Tininver lime-works are the property of Mr. 
 Kemp, Keith, and have been carried on by him for many years. 
 The Parkmore works are situated on the east side of the railway 
 viaduct which crosses the river Piddich to the north of Dufftown, 
 and the kilns and lime stores are connected with the Great North 
 of Scotland Eailway by suitable sidings. The Tininver quarry is 
 close to the river Fiddich, below Dufftown. In both these quarries 
 the quality of the rock is excellent, and they are both working the 
 same zone of limestone. Their joint annual output of marketable 
 lime varies from nine to ten thousand tons per annum. Its quality 
 is known in the trade as " a first class Scotch lime." 
 
 The lime produced at these works is chiefly used by builders and 
 plasterers, and in a lesser degree for agricultural and gas purifying 
 
JEconomic Products. 75 
 
 purposes. It is consigned'to all the districts served by the Great 
 North of Scotland and Highland Eailways between Aberdeen and 
 Caithness. 
 
 At these joint works eight kilns of the " Clamp " type are 
 constantly employed. When the Parkmore quarry was first 
 opened out, continuous burning kilns were erected. These were 
 similar to those at present in use all over the Carboniferous Lime- 
 stone districts of the North of England. After a few years' trial 
 these kilns were abandoned and the present type adopted. This 
 change was rendered necessary, partly on account of the require- 
 ments of the North of Scotland lime trade and also the difficulty 
 of getting the proper class of fuel necessary for their most economical 
 working. 
 
 Analysis of limestone from Tininver Quarry, Dufftown, by 
 J. Falconer King, City Analyst, Edinburgh : — 
 
 *Lime - 54-43 
 
 Magnesia 1-05 
 
 Iron oxide '35 
 
 Carbonic acid 43'15 
 
 Sulphuric anhydride - trace 
 
 Organic matter trace 
 
 Water -08 
 
 Insoluble matter I'OO 
 
 lOO'Oe 
 
 This limestone will, when burned, form a lime well suited for 
 building, agricultural, or gas-purifying purposes. 
 
 (Signed) J. Falconer King. 
 
 Analysis of limestone from Braehead Quarry, Keith, by J. Falconer 
 King : — 
 
 Carbonate of lime 94-41 
 
 „ „ magnesia 1'72 
 
 „ „ iron trace 
 
 Lime as sulphate, silicate, etc. 1-17 
 
 Sulphuric acid -12 
 
 Organic matter and loss 44 
 
 Moisture -06 
 
 Silica and insoluble matter 2 '08 
 
 100-00 
 
 [Communioated by Mr. Jamea Kemp, Keith, with permission to publish.] 
 
 The Upper Old Eed Sandstone affords a good freestone, which 
 has long been quarried at Dallas and Plusoarden. A rougher stone 
 of local use is obtained from the lower strata near Fochabers. 
 
 The slaty phyllites have been wrought for roofing-slate at New- 
 mill, Mulben, and Tarrymouut, but the large quarry at the last- 
 
 * Equal to carbonate of lime, 97 '20 per cent. 
 
76 Hxptanation of Sheet 86. 
 
 named locality is now abandoned. The black schists have also 
 been extensively quarried on the western ' slope of the Scalp Hill 
 near Auchindoun Castle and to the north-east of the Hill of 
 Mackalea. Granite and gneiss are quarried for local building 
 purposes at Euthrie and on the Blue Hill near Aberlour ; but 
 dressed stone for liatels and ashlar work is imported from the 
 Elgin district. 
 
 Bkick Clay. — A considerable manufacture of bricks, tiles, and 
 drain-pipes is carried on at Craigellachie, where terra-cotta ware is 
 also made from the finer parts of the glacial clay. 
 
 J. S. G. W. 
 
 Roads, Highvrays, and Road Metal. 
 
 With the exception of the three small areas of Elginshire and 
 the narrow strip of Aberdeenshire along the eastern edge of the 
 map, all the roads and highways on the east side of the river Spey 
 in this sheet are included within the second or Keith district of the 
 county of Banff.* These roads are classed as I., II., III. They 
 have, along with their bridges, been much improved within the 
 past ten or twelve years, and are now throughout the whole district 
 in a very fair and passable condition. Three years ago a steam- 
 roller and plant were purchased by the County Council, and in the 
 parishes where there is traction engine and other heavy traf&c the 
 former unsatisfactory condition of these roads has been immensely 
 improved by rolling. The road metal used in the different districts 
 is very diversified in character. This is partly due to the cost of 
 carriage for any considerable distance from the good quarries, and 
 also to the initial expense which would be incurred in providing 
 means of access to places where suitable rock is situated at some 
 distance from a public highway. 
 
 * Under the Local Government (Scotland) Act 1889. 
 
Table Showing Localities and Class of Metal used in the 
 EoAD Districts, Upper Banffshire — Sheet 85. 
 
 From information supplied by Mr. Robert Davidson, Eoad Surveyor. 
 
 Name of District. 
 
 Locality. 
 
 Class of Metal. 
 
 Notes. 
 
 Inveravon, 
 
 Hill above Blairfindy 
 Lodge. 
 
 Hard Slate. 
 
 
 Tombae. 
 
 Quartzite. 
 
 
 
 Tombrechaohie. 
 
 Quartzite. 
 
 
 
 Hill of Craggan. 
 
 Blue Whinstone. 
 
 Fine hard quality for 
 
 
 Tervieside. 
 
 Limestone. 
 
 road metal. 
 
 
 Bed of River Avon. 
 
 Various water-worn 
 stones. 
 
 
 
 Ballindallooh. 
 
 Land Stones and Gravel. 
 
 
 
 At different centres. 
 
 " Heathen" Boulders. 
 
 
 
 Morinsh. 
 
 Limestone. 
 
 
 Aberlour, 
 
 Ruthrie. 
 
 Granite. 
 
 
 
 Above Ry ehilloch, Blue 
 
 Granite. 
 
 
 
 Hill. 
 
 
 
 
 Bridge of Fiddich. 
 
 Granite and Quartzite 
 mixed. 
 
 
 
 Loop. 
 
 Gravel Pits. 
 
 Good Quality. 
 
 
 Eringarrow 
 
 Gravel Pits. 
 
 Good Quality. 
 
 
 Farm of Hatton. 
 
 Gravel Pits. 
 
 Good Quality. 
 
 
 Buchromb. 
 
 Gravel Pits. 
 
 Good Quality. 
 
 
 River Spey, Bed of. 
 
 Various water-worn 
 stones. 
 
 
 
 At different centres. 
 
 Land stones. 
 
 
 Mortlaoh, 
 
 Tininver Quarry, Duff- 
 town. 
 Richmond Quarry, 
 
 Limestone. 
 
 
 
 Limestone. 
 
 
 
 Dufftown. 
 
 
 
 
 Bogbuie. 
 
 Quartzite. 
 
 
 
 Little TuUoch. 
 
 Old Red Sandstone 
 
 
 
 Parkmore. 
 
 Conglomerate 
 Limestone. 
 
 
 
 Lochpark. 
 
 Limestone. 
 
 
 
 Westerton. 
 
 Gravel. 
 
 
 
 River Fiddich, Bed of. 
 
 Various water-worn 
 stones. 
 
 
 
 At different centres. 
 
 Land stones. 
 
 
 Glenrinnes, 
 
 Bridge of Lettoch. 
 
 Quartzite. 
 
 Fine quality for road 
 
 
 Glack Harness, 
 
 Granite. 
 
 metal purposes. 
 
 
 Rinaitin. 
 
 Limestone. 
 
 
 
 At different centres. 
 
 Land stones. 
 
 
 Cabrach, 
 
 Ardwell. 
 
 Gabbro 
 
 
 
 Bridge of Ardgallie. 
 
 Serpentine. 
 
 
 
 Glaok of Balloch. 
 
 Quartzite. 
 
 
 
 River Deveron, Bed of. 
 
 Various water-worn 
 stones. 
 
 
 
 River Deveron, Bed of. 
 
 Gravel. 
 
 
 
 At different centres. 
 
 Land stones. 
 
 
 Botriphnie, 
 
 Looh Park. 
 
 Limestone. 
 
 
 
 Bum of Towiemore. 
 
 Limestone. 
 
 
 
 Above Drummuir Castle 
 
 Quartzite. 
 
 
 
 Merchants Croft. 
 
 Quartzite. 
 
 Decomposed. 
 
 
 Mains of Davidston. 
 
 Mica-schist 
 
 
 
 Edlntore. 
 
 Black-schist. 
 
 
 
 Pitlurg. 
 
 Mica-schist. 
 
 
 
 Pitlurg. 
 
 Gravel. 
 
 
 
 At different centres. 
 
 Land stones. 
 
 
 Boharm, 
 
 Tauchers MUl. 
 
 White Quartzite. 
 
 Fine quality for road 
 purposes. Good quarry. 
 
 
 Auchroish Wood. 
 
 White Quartzite. 
 
 Do. do. do. 
 
 
 Brae above Popine. 
 
 White Quartzite. 
 
 
 
 Knockandhu. 
 
 Gravel. 
 
 
 
 Ferranderran. 
 
 Gravel. 
 
 
 Keith, - 
 
 Black Hillock. 
 
 Limestone. 
 
 
 
 Eosarie. 
 
 Quai-tzite. 
 
 
 
 Blackhill Wood. 
 
 Quartzite. 
 
 
 
 Above Newraill. 
 
 Hard Slaty Phyllites. 
 
 
 
 Loauhead. 
 
 Hard Slaty Phyllites, 
 
 
 
 At different centres. 
 
 Land stones. 
 
 
 
 Keith. 
 
 Augen-gneiss. 
 
 
78 Explanation of Sheet 85. 
 
 Tabular Statement of Eoad Metal used in the County of 
 Elgin— Sheet 85. 
 
 From information supplied by Mr. Alexander Hogg, C.E., County Eoad Surveyor. 
 
 Parish. 
 
 Locality. 
 
 Class of Metal. 
 
 Remarks. 
 
 Bellie, 
 
 FromFoohabers towards 
 
 Stream stones. 
 
 Fair good quality. 
 
 
 Keith. 
 
 
 Taken from Fochabers 
 Burn. 
 
 
 Fochabers, 
 
 Stream and field stones. 
 
 From River Spey and 
 heaps carted off land. 
 Fair good quality. 
 
 
 Tynet. 
 
 Stream stones. 
 
 From Fochabers Burn 
 and other streams. 
 Fair good quality. 
 
 Speyraouth, 
 
 Dipple. 
 
 Do. and field stones. 
 
 From River Spey and 
 heaps carted offland. 
 . Fair good quality. 
 
 Rothes, 
 
 Orton. 
 
 Do., River Spey. 
 
 Fair good quality. 
 
 
 Rothes Police Borough 
 
 Blue grey quartz-schists 
 
 Bottom of quarry good 
 
 
 Crofts Quarry-. 
 
 
 quality ; veins of 
 Barytes. 
 
 
 Dandaleith. 
 
 Stream stones, R. Spey. 
 
 Fair good quality. 
 
 
 Birchfield. 
 
 Water-worn stones and 
 
 Pits N.E. of Birchfield; 
 
 
 
 strong pit gravel. 
 
 good rook could be 
 got to west. 
 
 Elgin, 
 
 Pluscarden. 
 
 Stream and pit stones. 
 
 Of fair quality ; from 
 glacil deposits ; good 
 rocktowestof Abbey. 
 
 Very superior rock for 
 
 Kinloss South, 
 
 Lawrenceton Quarry. 
 
 Hard Quartzo - fels- 
 
 
 
 pathio gneiss with 
 
 road metal ; the best 
 
 
 
 small granite veins. 
 
 in the county. 
 
 Forres 
 
 Wester New Forres. 
 
 Do. do. do. 
 
 Do. do. do. 
 
 Eafford 
 
 Briach to Rafford from 
 Lawrenceton and 
 
 
 
 
 Wester New Forres. 
 
 Do. do. do. 
 
 Do. do. do. 
 
 
 Other parts of Parish. 
 
 Water-worn and land 
 stones. 
 
 Good quality. 
 
 Dallas, 
 
 The whole Parish. 
 
 Do. do. do. 
 
 Do. 
 
 Birnie, 
 
 The whole Parish. 
 
 Do. do. do. 
 
 Do. Good 
 
 
 • 
 
 
 rock available to the 
 E. of Shongle. 
 
 Knockaudo, 
 
 Easter Elohies Quarry. 
 
 Decomposing granite. 
 
 Good quality. 
 
 
 Do. do. 
 
 Water-worn and land 
 stones. 
 
 Do. 
 
 
 Quarry near Carron 
 
 Granite, close-grained. 
 
 Rather soft. 
 
 
 Road Station. 
 
 
 
 
 Carron. 
 
 Water-worn and land 
 stones. 
 
 Good quality. 
 
 
 Archiestown. 
 
 Do. do. do. 
 
 Do. 
 
 
 Cardow. 
 
 Do. do. do. 
 
 Do. 
 
 
 KirdellB. 
 
 Do. do. do. 
 
 Do. 
 
 
 Blacksboat. 
 
 Do. do. do. 
 
 Do. 
 
 Inverallan and 
 
 
 
 
 Advie, 
 
 The whole Parish. 
 
 Do. do. do. 
 
 Do. 
 
Mineral Wells. 79 
 
 Mineral Wells 
 
 Chalybeate springs are of frequent occurrence along the outcrop 
 of the ferruginous black-schists. Amongst the best known of 
 these are the Priest's Well near Duffbown ; a well at Tulloch, west 
 of Kininvie ; and a very strong iron spring which rises in the 
 middle of a peat moss west of Brown Hill in the Lower Oabrach, 
 and has a great local reputation for its medicinal qualities. The 
 water of the burn below Tulloch is also strongly impregnated with 
 alum derived from the decomposition of the iron pyrites in the 
 black schist. 
 
 Iron. 
 
 A thin vein of ironstone was at one time wrought on the western 
 base of Ben Aigan, near Arndilly. J. S. G. W. 
 
Appendix. 81 
 
 APPENDIX. 
 
 PART I. 
 
 PAL^ONTOLOGIOAL. 
 
 Note on the Fossil Fishes of the Old Red Sandstone 
 OF Scotland by Dr. Traquair, F.R.S. 
 
 Mr. Home having asked me to furnish a brief statement regarding 
 our knowledge of the distribution of fossil fishes in the Scottish Old 
 Red Sandstone, I submit the following notes, which give, in fact, the 
 substance of a paper read by me at the meeting of the British Asso- 
 ciation at Glasgow in September, 1901. 
 
 There are three distinct fish-faunae in the rocks designated " Old 
 Red Sandstone " in Scottish geology. The first is that of the Lower 
 Old Red Sandstone of the central valley of Scotland, typically developed 
 in Forfarshire ; its characteristic fishes being species of Cephalaspis and 
 Pteraspis, as well as Acanthodians of the genera Climatius, Parexus, 
 Euihacanihus, Ischnacomthvs, and Mesacanthus. This fish-fauna is 
 closely allied to that of the Lower Old Red Sandstone of the West of 
 England, which is again linked with those of the Lower Devonian of 
 Spitzbergen, of Podolia, and of Campbelltown in Canada. It differs, 
 however, from that of the Lower Devonian (Oorniferous Limestone) of 
 the United States markedly, in the absence from the latter of the 
 characteristic Pteraspidians and Oephalaspidians, nor does the "Oor- 
 niferous " show any Acanthodians unless MachcBracanthus be one. It 
 must be remembered, however, that the Oorniferous Limestone is of 
 purely marine origin, having been formed under conditions very 
 different from those under which the Lower Old Red of Forfarshire or 
 the Lower Devonian of Canada were deposited. 
 
 The second great Scottish Old Red fish-fauna is that of the 
 Orcadian series, which lies to the north of the Grampians, and this 
 fauna is strikingly different from that of the Forfarshire beds. Only 
 two genera and not a single species are common to both. The 
 occurrence near Thurso of species belonging to the Forfarshire Acan- 
 thodian Pwrexus recurvus, Agass, has been mentioned by Sir A. Geikie 
 on the authority of the late Mr. 0. W. Peach, but there must be a 
 mistake of identification here, for I have gone over all the specimens of 
 Caithness fish-remains, collected by Mr. Peach, which are in the British 
 Museum, in the Museum of Practical Geology, and in the Edinburgh 
 Museum of Science and Art, without finding a trace of Parexus, nor 
 have I seen it in any other collection of fossils from the Orcadian beds. 
 Parexus recurvus does, however, occur in the Lower Old Red Sandstone 
 of Herefordshire. 
 
 Not only are the Forfarshire and Orcadian fish-faunse distinct, but 
 their respective " facies " seem to point in different directions. The 
 
 L 
 
82 Explanation of Sheet 85. 
 
 Pteraspidse and Cephalaspidfe are also characteristic Upper Silurian 
 families, as in the West of England and elsewhere. On the other hand, 
 -the Orcadian fish-fauna, characterised by Asterolepidie, {Pteriohthys, 
 Microbrachius), Acanthodidai (Cheiraoanthm, Diplacomthus), Osteolepidse 
 {Osteolepis, Diplopterus, Thursius), Rhizodontidse {Gyroptychius, Tristi- 
 chopterus), Holoptychiidse {Glyptolepis), Ctenodontidse {Dipierus) 
 Coccosteidse {Coccosteus, Eomosteus) Palseoniscidse {Cheirolepis), is, as 
 already remarked by Mr. J. W. Evans, more allied to that of the Upper 
 Old Red, to which it is linked, we may say, by the set of fishes found 
 in the Upper Devonian of Scaumenao Bay in Canada. Of the two 
 genera which are common to the Orcadian and Forfarshire beds, namely 
 Cephalaspis and Mesacamthus, both also occiu? in these Canadian Upper 
 Devonian strata, but it must be noted that Cephalaspis, so characteristic 
 a Lower Devonian genus, is known from the Orcadian and Scaumenac 
 Bay strata only by a single unique specimen in each case, namely, C. mag- 
 nifica, Traq., and G. laticeps, Traq., respectively. It may also be added 
 that Goccosteus, though not occurring in Forfarshire, is, like Cephalaspis, 
 a genus which goes through the entire formation, being found not only 
 in the Orcadian series, but also in the Lower Devonian of Germany 
 (Hunsriickschiefer) and the United States (Corniferous) as well as in 
 the Upper Devonian of Canada, and the Upper Old Red of Scotland. 
 
 Nor does the Orcadian fish-fauna present any greater affinity to any 
 of the Lower Devonian fish-faunse of Europe or America than it does to 
 those of Forfarshire or Herefordshire. Scanty, however, as is the fish- 
 material collected from the Middle Devonian of the Eifel, it is inter- 
 esting to note the occurrence there of a well marked species of 
 Pteriohthys (Ft. Rhenanus, Beyrich), and of a species referred to 
 Osteolepis by Professor von Koenen, both being prominent Orcadian 
 genera. 
 
 The third great fish- fauna is that of the Upper Old Red Sandstone, 
 characterised by Psammosteus, Asterolepis, Boihriolepis, Phyllolepis, 
 Glyptopomus, Saiifipterus, Soloptychius, and Phaneroplewon, which 
 place this series of rocks on the same general horizon as the Upper 
 Devonian of the North-west of Russia, the Fameimien of Belgium, and 
 the Catskill of the United States— the fish-remains of the Shetland beds, 
 however, pointing to a position corresponding to that of the Chemung 
 group (Upper Devonian) of the Western Continent. Bothriolepis and 
 Holoptychius are the most prominent genera of the Upper Old Red, and 
 it is interesting to observe that, though the fish-fauna of the Upper 
 Devonian of Scaumenac Bay has many points of afiinity with that of 
 the Orcadian series, the only Asterolepid present is a Bothriolepis {B. 
 Canadensis, Whiteaves). 
 
 The statement by the late Sir Frederick M'Ooy (Report on Palaeon- 
 tology in Ann. Rep. of Secretary for Mines, Victoria, 1889) as to the 
 occurrence at Mansfield, in Australia, of a Pteraspis, and of fishes 
 specially allied to Cephalaspis, Diplacanthus, and Cheirolepis in the 
 same beds with Palseoniscidse of Carboniferous type is clearly founded on 
 erroneous determinations. The whole collection on which this Report 
 was based has just been forwarded to Dr. Smith Woodward for descrip- 
 tion, and I have his permission to state that, having together carefully 
 looked over all the specimens, we found no trace of any Pteraspidian or 
 Cephalaspidian, or, indeed, of anything else characteristically Devonian. 
 The fades of the fish-fauna represented in this collection is unmis- 
 takably Ca/rhoniferous. 
 
 R, H. TRAQUAIR. 
 
Appendix. 83 
 
 List op the Fossil Fishes occuERiNa at Tynet Burn, in the Orcadian 
 Series, by Dr. K. H. Traquair, F.R.S. 
 
 Pterichthys MilUri, Agass. 
 
 „ productus „ 
 
 ,, oblongus^ „ 
 
 Cheiracanthus MttrcMsoni, Agass. 
 
 „ latus, Egert. 
 
 DiplacantMis striatus, Agass. 
 Osteolepis macrolepidotxis, Agass. 
 
 Diploptems Agassizii, Traill. 
 Oyroptychius microl&pidotus (Agass. ). 
 OlyptoUpis Uptopterus, Agass. 
 DipteriLs Valenciennesii, Sedgw. and 
 
 Murch. 
 Ooccosteus decipiens, Agass. 
 Cheirolepis Trailli, Agass. 
 
 Species occurring at Gamrie, and elsewhere on the Moray Firth, 
 but which I have not seen from Tynet Burn as yet : — 
 
 Diplacanthus Icnigispinua, Agass. 
 „ tenuistriatus, Traq. 
 
 K. H. T. 
 
 Note on the Fossil Plants op the Old Red Sandstone 
 OF Scotland by Mr. R. Kidston, F.R.S. 
 
 The Fossil Plants of the Old Red Sandstone of Scotland show a 
 clearly defined three-fold division of this formation. The flora is not 
 numerous in true species, for many of the species which have been 
 made have been founded on material far too imperfect to be of any 
 scientific value. 
 
 Records of the occurrence of Lejndodendron, C'alamites, etc., in the 
 Old Red Sandstone of Scotland, must, I am afraid, be cancelled. In 
 some cases I have seen the specimens on which the record was made, 
 and even with the most liberal interpretation of these genera, it is 
 impossible to admit the specimens into the genera in which they had 
 been placed. 
 
 The upper division is characterized by the occurrence of Archmop- 
 teris kibernica, Forbes sp., and contains an altogether distinct flora from 
 that of the two underlying divisions. 
 
 The Orcadian division contains a very common plant, which I 
 recorded as Psilophyton rohvMius, Dawson. Better and more perfect 
 specimens have shown me that I was in error, and that the plant I had 
 believed to be Psilophyton rohustius, Dawson, was the lower portion of 
 the plant, whose upper part was the PtUophyton Thomsoni, Dawson, 
 whose stem is the Caulopteris Peachii of Salter. This species is very 
 common in the Caithness flags, and is entirely absent from the Perth- 
 shire and Forfar Old Red strata. The so-called Lycopodifes Milleri, 
 Salter, and a few other species are also peculiar to the Caithness flags. 
 
 The Lower or Perth-Forfar Old Red is characterized by the presence 
 of Psilophyton princeps, Dawson, and var. ornatum, Dawson, Psilophyton 
 rohustius, Dawson, Arthrostigma gracilis, Dawson, Z osier ophyllum 
 Myrtmiianum, Penhallow, and Parka decipiens, Fleming, etc. 
 
 A.S far as I know at present, each of these divisions is characterized 
 by a flora peculiar to itself, but the whole subject requires a thorough 
 revision in the light of more recent discoveries. 
 
 R. KIDSTON. 
 
Eos/plcmation of Sheet 85. 
 
 PART II. 
 
 List of Publications Referring to the Geology and Mineralogy 
 OF THE District included in Sheet 85. 
 
 1775. History of the Province of Moray. Shaw. 
 
 1830. " An account of the Great Floods of August 1829 in the Province 
 of Moray and the adjoining districts," by Sir Thos. Dick 
 Lauder, Bt. 
 
 1835. " Essay on the Geology of Moray," by John Martin. Highland 
 
 SoG. Trans., Vol. V,, new series. 
 
 1836. "On the Geology of Moray," same author. Quart. Journ. 
 
 Agricultwre, No. XXXV. 
 
 1840. Geological Map of Scotland. John MaccuUoch, F.R.S. 
 
 1842. " Sketch of the Geology of Moray," by Patrick Duflf. 
 
 1842. " The Geognosy of Ban£Fsbire," by R. F, H. Cunningham. Trans. 
 HigMcmd Soc., Vol. XIV. 
 
 1842. " On the Relations of the different parts of the Old Red Sand- 
 stone in which Organic Remains have recently been Discovered 
 in the Counties of Murray, Nairn, Banff and Inverness," by J. 
 G. Malcomson, M.D. Proe. Geol. Soc, Vol. III. 
 
 1858. " On the Sandstones of Morayshire and Elgin containing Rep- 
 
 tilian Remains, and on their Relations to the Old Red Sand- 
 stone of that County," by Sir R. I. Murchison. Qua/rt. Journ. 
 Geol. Soc, Vol. XV., p. 419. 
 
 1859. " The Geology of the Lower or Northern part of the Province of 
 
 Moray," by Dr. Gordon of Birnie. Edin. New Phil. Jown.. 
 Vol. IV. 
 
 1860. "Notes on Fossiliferous Localities of the Old Red Sandstone of 
 
 the East of Scotland," Gregory. The Geologist, Vol. III., pp. 
 142-148. 
 
 1866. " Geology of the North of Scotland," by Prof. Nicol. 
 
 1871. " On the Older Metamorphic Rocks and Granite of Banffihire," 
 by T. F. Jamieson, F.G.S. ' Quart. Jowrn. Geol. Soc, Vol. 
 XXVII., p. 101. 
 
 1877. Same title and author. Geol. Mag., Vol. VIII., p. 134. 
 
Appendix. 85 
 
 1871. " On the Old River Terraces of the Spey " by Kev. Thos. Brown. 
 Proc. Roy. Soc. Edin., Vol. VII., p. 399. 
 
 1872-3. " Reports of the Committee on Boulders appointed by the Royal 
 Society of Edinburgh," D. Milne Home. Pvoc. Roy. Soc. 
 Edin., Vols. VII., VIII. 
 
 1874. "On the Last Stage of the Glacial Period in North Britain," by 
 T. F. Jamieson. Quart. Journ. Geol. Soc, Vol. XXX. 
 
 1878. " On the Transportation of Rocks found on the S. Shore of the 
 Moray Firth," by W. Jolly. Communicated to the Report of 
 Boulder Committee. Proc. Roy. Soc. Edin., Vol. X., p. 178. 
 
 1878. "The Old Red Sandstone of Western Europe," by Sir Arch. 
 Geikie, F.R.S. Trans. Roy. Soc. Edin., Vol. XXVIII., p. 345. 
 
 1879-83. "Chapters on the Mineralogy of Scotland," Prof. M. F. 
 Heddle. Trans. Roy. Soc. Edin., Vols. XXVIII.-XXX. 
 (Contains several references to mineral localities within the 
 Sheet.) 
 
 1882-84. " Reports of the Boulder Committe of the Royal Society." 
 Proc. Roy. Soc. Edin., Vols. XI., XII. 
 
 1894. "Annvial Report of the Geological Survey for the year 1893," 
 p. 264. 
 
 1896. "The Sands and Sandstones of Eastern Moray," by Wm. 
 Mackie, M.D. Trajis. Edin. Geol. Soc, Vol. VII. 
 
 1896. "The Extinct Vertebrate Animals of the Moray Firth Area," by 
 
 R. H. Traquair, M.D., F.R.S. Fauna of the Moray Basin, 
 Harvie-Brown and Buckley, Vol. II. 
 
 1897. " Additional Notes on the Fossil Fishes of the Upper Old Red 
 
 Sandstone of the Moray Firth Area," R. H. Traquair, M.D., 
 F.R.S. Proc Roy. Phys. Soc Edin., Vol. XIII. 
 
 1899. " Seventy Chemical Analyses of Rocks, (chiefly from the Moray 
 
 Area) with Deductions," by W. Mackie, M.D. Trans. Edin. 
 Geol. Soc, Vol. VIII. 
 
 1900. " On Differences in Chemical Composition between the Central 
 
 and Marginal Zones of Granite Veins, with further evidence 
 of exchanges between such Veins and the Contact Rocks," by 
 the same author. Trans. Edin. Geol. Soc, Vol. VIII. 
 
 1900. "Notes on the Distribution of Erratics over Eastern Moray," by 
 
 the same author. Trans. Edin. Geol. Soc, Vol. VIII. 
 
 1901. "The River Spey," by Lionel W. Hinxman. Scottish Geogra- 
 
 phical Magazine, April, 1901. 
 
 1901. "The Interstitial or Cementing Substances in the Elgin Sand- 
 stones," by W. Mackie. M.D. Trans. Northern Assoc of 
 Scientific Societies. 
 
86 
 
 Bxplanation of Sheet 85. 
 
 PART III. 
 
 List op Microscopic Sections Peepabed peom Rocks Collected 
 IN Sheet 85. 
 
 The Newer Gh'anites and Diwites. 
 
 No. 
 
 Name. 
 
 Locality. 
 
 
 9568. 
 5248. 
 
 Biotite Granite. 
 Do. 
 
 Glack Harness, between Round 
 
 Hill and Meikle Conval. 
 Carron, Strathspey. 
 
 See p. 36. 
 See p. 37. 
 
 9554. 
 
 Do. 
 
 Ruthrie, Aberlour. 
 
 See p. 36. 
 
 9567. 
 
 Do. 
 
 Burn of Rothes, below Netherly. 
 
 See p. 38. 
 
 9598. 
 9552. 
 
 Muscovite Granite. 
 Quartz Diorite. 
 
 Nether Cluny, 2 miles S.S.W. of 
 
 Dufftown. 
 i mile S. of Dandaleith. 
 
 See p. 37. 
 See pp. 37, 38. 
 
 9551. 
 
 Do. 
 
 Do. do. 
 
 See pp.37,38. 
 
 9563. 
 
 Do. 
 
 Do. do. 
 
 See pp.37,38. 
 
 9608. 
 
 Do. 
 
 Hill above Cone Rock, Rothes. 
 
 See p. 33. 
 
 9607. 
 
 Do. 
 
 B. of Stob HiU. 
 
 See pp.33,39. 
 
 9550. 
 
 Do. 
 
 Netherly, Burn of Rothes. 
 
 See pp. 38-41. 
 
 16.32. 
 
 Do. 
 
 Do. do. 
 
 See pp.38-41. 
 
 1633. 
 
 Do. 
 
 Do. do. 
 
 See pp.38-41. 
 
 1634. 
 
 Do. 
 
 Do. do. 
 
 See pp.38-41. 
 
 9606. 
 9605. 
 7769. 
 
 Biotite Granite. 
 
 Diorite, with inclusions of 
 
 schist. 
 Camptonite, 
 
 Railway cutting, B. of tunnel 
 
 CraigeUachie. 
 Milltown of Ruthrie, Abenour. 
 
 B. bank of Spey, HoUybush Pool, 
 Aikenway. 
 
 See p. 39. 
 See p. 37. 
 See p. 41. 
 
AppeTidix. 
 
 87 
 
 The Foliated Igneous Masses. 
 
 No. 
 
 Name. 
 
 Locality. 
 
 
 1758. 
 
 Augen Gneiss. 
 
 Keith, Banffshire. 
 
 See p. 44. 
 
 9548. 
 
 Hornblende Schist. 
 
 KingshaHgh, Blackwater. 
 
 See p. 46. 
 
 9600. 
 9601. 
 
 Serpentine. 
 Epidiorite. 
 
 Blackwater, 2 miles above Ardwell 
 Bridge 
 Do. Do. 
 
 See p. 45. 
 See p. 44. 
 
 2963. 
 
 Flaser Gabbro. 
 
 Blackwater, 1 mile N. of Lodge. 
 
 Seepp.30,44. 
 
 2964. 
 
 Do. 
 
 Do. Do. 
 
 See p. 45. 
 
 9549. 
 9565. 
 
 Calc Hornblende Schist. , 
 Hornblende Schist. 
 
 300 yards above bridge over Black- 
 water, Ardwell. 
 Bum at Findouran, Burn Treble. 
 
 See p. 46. 
 See p. 29. 
 
 1788. 
 
 Hornblende Eock. 
 
 Shenwell, Blackwater. 
 
 See p. 45. 
 
 9563. 
 
 Diallage Peridotite. 
 
 Craigdorney, River Deveron. 
 
 See p. 45. 
 
 Metamorphic Schists {Moine Schists). 
 
 No. 
 
 Name. 
 
 Locality. 
 
 
 2077. 
 
 Biotite Gneiss. 
 
 Craigellachie entting. 
 
 See p. 32. 
 
 2078. 
 
 Do. 
 
 Do. do. 
 
 See p. 32. 
 
 5249. 
 
 Muscovite Biotite Gneiss. 
 
 Blue Hill, Aberlour. 
 
 See p. 32. 
 
 5250. 
 1635. 
 
 Biotite Gneiss and Biotite 
 
 Granite. 
 Garnet Muscovite Gneiss. 
 
 Slack of Ballanteem, Aberlour. 
 Rothes Burn. 
 
 See p. 
 See p. 28. 
 
 9556. 
 
 Quartzite. 
 
 Hunt Hill. 
 
 See p. 31. 
 
 9560. 
 
 Quartz Felspar Hornfels. 
 
 Netherly, Burn of Rothes. 
 
 See p. 51. 
 
 9558. 
 
 Biotite Hornfels. 
 
 Do. do. 
 
 See p. 51. 
 
 9561. 
 
 Do. 
 
 Do. do. 
 
 See p. 51. 
 
 9559. 
 
 Cordierite Hornfels. 
 
 Do. do. 
 
 See p. 52. 
 
 9609. 
 
 Andalusite Hornfels. 
 
 Do. do. 
 
 See p. 53. 
 
 9610. 
 
 Quartzite. 
 
 North end of Craigellachie Bridge. 
 
 See p. 51. 
 
 5251. 
 
 Biotite Granite and Biotite 
 Schist. 
 
 Ballanteem, Aberlour, 
 
 Seep. 61. 
 
JExplanation of Sheet 85. 
 
 Banffshire Series. 
 
 No. 
 
 Name. 
 
 Locality. 
 
 
 9556. 
 
 Grit. 
 
 Allt Deach, Ardwell. 
 
 See p. 23. 
 
 1759. 
 
 Micaceous Grit. 
 
 Drummuir, S. of Keith. 
 
 See p. 48. 
 
 981. 
 
 Schistose Grit. 
 
 Eailway cutting, Mulben. 
 
 See p. 48. 
 
 93-3. 
 
 Phyllite, 
 
 Do, do. 
 
 See pp.21,48. 
 
 934. 
 
 Do, 
 
 Do, do. 
 
 See pp.21,48. 
 
 935. 
 
 Do, 
 
 Do. do. 
 
 See pp.21,48. 
 
 936b. 
 
 Do. 
 
 Do. do. 
 
 See pp.21,48. 
 
 9356. 
 
 Do. 
 
 Do. do. 
 
 See pp.21,48. 
 
 1761. 
 
 Qnartzite, with agate veins. 
 
 Cone Hill, Rothes, 
 
 See p. 13. 
 
 2074. 
 
 Mica Schist. 
 
 Haugh's Quarry, Keith, 
 
 See p. 22. 
 
 1765. 
 
 Limestone. 
 
 Blackhillock Quarry, Keith. 
 
 See pp. 18,48. 
 
 1768. 
 
 Micaceous Limestone. 
 
 Do. do. 
 
 See pp. 18, 48. 
 
 1766. 
 
 Do. do. 
 
 Do. do. 
 
 See pp.18, 48. 
 
 1767. 
 
 Do. do. 
 
 Do. do. 
 
 See pp.18,48. 
 
 2091. 
 
 Black Schist with Tremolite. 
 
 Boharm. 
 
 See pp.19,50. 
 
 9594. 
 
 Do. do, Actinolite. 
 
 Belnagarrow, 2^ miles N.E. of Craig- 
 
 ellachie, 
 1 mile N.W, of Bdington Ho., 2i 
 
 miles S. of Keith. 
 Stream between Blackhillock and 
 
 TuUoch, 2 miles N. of Dufftown. 
 Near Tulloohallum, Dufftown. 
 
 See pp. 19, 50. 
 
 9597. 
 9596. 
 9564. 
 
 Black Schist. 
 
 Do, 
 Calc-silioate Hornfels, 
 
 See p. 20. 
 
 See p. 19. 
 
 Seepp.50,56. 
 
 9604, 
 
 Do, do. 
 
 Railway cutting E. of Dufftown. 
 
 See pp.50,56. 
 
 9603. 
 
 Chiastolite Slate. 
 
 Ardwell Inn, Blackwater, 
 
 See pp. 53 54. 
 
 9603. 
 
 Biotite Hornfels. 
 
 Above Blackwater Bridge, Ardwell, 
 
 See p. 56. 
 
 S599 
 and 
 9599J. 
 9595. 
 
 Andalusite and Staurolite 
 Schist. 
 
 Calcareous Grit. 
 
 Blackwater, 2 miles above Ardwell 
 Bridge. 
 
 Little Newton, 2 miles N.E. of 
 Craigellachie. 
 
 See p. 54. 
 See p. 50. 
 
INDEX, 
 
 Abeeloub, 1, 6, 31, 36. 
 Aigan, Ben, 1, 3, 13. 
 Aikenway, 6, 13, 35, 72. 
 AUt Arder, 4, 70. 
 Allt Gheallaidh, 2, 26. 
 Alluvial deposits, 69, 71, 72. 
 Alum, 19, 79. 
 Analyses — 
 
 of granite veins and contact rocks. 
 
 28. 
 -~ — of limestones, 74, 75. 
 
 of diorites and granites, 43. 
 
 of metamorphic schists, 57. 
 
 Andalusite schist, 53. 
 Andesite, 11. 
 Ardwell, 21, 45, 53. 
 Area embraced in map, 1. 
 Arndilly, 13, 65, 67. 
 Arrows, double-shafted, 24. 
 Auchindoun Castla 18, 20. 
 Augen gneiss, 10, 29, 31, 44. 
 Aultderg Burn, 67. 
 
 earth-pillars of, 70. 
 
 Avon, River, 2, 4, 72. 
 
 Back Bhkn of Rothes — 
 
 analyses of rocks from, 28, 57. 
 
 Banffehire series, 7, 10, 12-23. 
 
 area occupied by, 10. 
 
 plication of, 12. 
 
 petrography of, 47, 50. 
 
 • contact minerals in, 53. 
 
 Ballindalloch, 6, 25, 46. 
 Basic sills, 29, 30. 
 
 contact alteration produced 
 
 by, 21. 
 Ben Rinnes, 1, 3, 25, 34. 
 
 granite of, 31-34, 36. 
 
 • quartzite of, 25. 
 
 Black Hill, 16. 
 Black schist, 19-21. 
 
 petrologieal characters of, 48. 
 
 Blackwater, 23, 29, 30, 45, 47, 54. 
 Blue Hill of Aberlour, 32. 
 Boulders, distribution of, 65, 66. 
 Boulder clay, 66-68. 
 Breccia, fault, 13, 15. 
 Brick clay, 70. 
 
 Burn of Bothes, 28, 33, 38, 41, 51, 57. 
 Burn Treble, 15, 16. 
 
 Cairngorm granite, 33, 34, 36. 
 Calcite in hornblende-schist, 45. 
 Calc-silicate-hornfels, 50, 56. 
 Cardow, 70. 
 Carron, 34, 37. 
 Cairnacay, 23, 73. 
 Centres of dispersion, 65, 66. 
 Chemical analyses — 
 
 of granites, 28, 43. 
 
 of diorite, 43. 
 
 of contact rocks, 28. 
 
 ■= of limestones, 74, 75. 
 
 Chiastolite slate, 54. 
 Coire Seileach Burn, 25, 26. 
 Cone rock, 13, 28, 40. 
 Conval Hills, 1, 10. 
 
 glaciation of, 71. 
 
 Contact metamorphism, 50-53. 
 
 minerals due to, 53-56 . 
 
 Contemporaneous lava, 29, 62. 
 Cordierite-hornfels, 34, 51. 
 Corrosion of hornblende in diorites, 39. 
 Corryhabbie Buin, 21, 23. 
 Craigellachie, 2, 19, 32, 33, 41, 70. 
 Craigs of Callander, 3, 27. 
 Craigdorney, 29, 30, 45. 
 Craigs of Succoth, 29, 30. 
 Oromdale Hills, 1, 10, 25, 71. 
 
 D 
 
 Dallas, 5, 10, 63, 71, 72. 
 Dallas, Loch, 2, 69. 
 Dandaleith, 7, 33, 37, 72. 
 Davidston, Mains of, 23. 
 Deskie Hill, 25. 
 
 Deveron, River, 2, 5, 21, 23, 29. 
 Diorite, 11, 33, 34, 37-42. 
 
 of Netherly, 33, 38. 
 
 of Hill of Stob, 33, 39. 
 
 of Dandaleith, 33, 37. 
 
 of Three Burnshead How, 34. 
 
 analyses of, 44. 
 
 Dipple, 7, 58. 
 Dufftown, 5, 6, 15, 17, 20. 
 DuUan Water, 5, 17, 22. 
 Dykes, granite, 42. 
 
 E 
 
 Earth-Pillars of Aultderg, 70. 
 Economic products, 74-79. 
 — — brick clay, 76. 
 
90 
 
 Index. 
 
 Economic freestone, 75. 
 
 iron, 79. 
 
 limestone, 74. 
 
 mineral wells, 79. 
 
 road metal, 76, 77. 
 
 slate, 75. 
 
 Eildon Hill, 1, 27. 
 
 Epidiorite, 29. 
 
 — — petrographical character of, 45. 
 
 contact alteration by, 47. 
 
 Erratic blocks, 66. 
 
 FjIULTS, 3, 60. 
 
 Features due to faulting, 3. 
 
 glacial action, 3. 
 
 Fiddich, River, 2, 5, 14, 15, 17, 19, 20, 
 
 22. • 
 Fossil lists — 
 
 from Burgle House, 64. 
 
 from Hatton Quarry, 64. 
 
 from Pluscarden, 64. 
 
 from Scaat Craig, 64. 
 
 from Torrieston, 64. 
 
 from Tynet Burn, 83. 
 
 Foliated granite, 31, 44. 
 
 O 
 
 Gabbko, 30. 
 
 petrography of, 44. 
 
 Garbet Hill, 15. 
 
 Geikie, Sir A., 81. 
 
 Geological features, 3. 
 
 Gheallaidh, AUt, 2, 26. 
 
 Glen Fiddich, 14, 15, 18, 21, 23. 
 
 Glen Livet, 25. 
 
 Glen Markie, 15, 18, 21, 29. 
 
 Glen Rinnes, 16, 22, 68. 
 
 Glen of Rothes, 3, 6, 28, 60, 72. 
 
 Glacial drift, 65-71. 
 
 strise, 65. 
 
 lakes, 70. 
 
 Granite, 3, 10, 31-33, 36, 37. 
 
 of Ben Rinnes, 10, 31-36. 
 
 of Hunt Hill, 31. 
 
 of Buthrie, 36. 
 
 analyses of, 43. 
 
 petrography of, 36-38. 
 
 differentiation of, 33. 
 
 contact metamorphism produced 
 
 by, 34, 51. 
 
 foliated, 31, 44. 
 
 homblendio, 37. 
 
 Granulitic schists of Central Highlands, 
 
 24-28. 
 
 petrography of, 46, 47. 
 
 Graphitic schist, 19, 20, 48. 
 Gravels — 
 
 fluvio- glacial, 68-70. 
 
 alluvial, 72. 
 
 Grits, 16, 23, 47, 48. 
 GtJNN, W., 46. 
 
 H 
 
 Hatton Quakby, fossils from, 64. 
 Herricks Moss, 14, 68. 
 Hillof Stob, 11, 31, 33. 
 
 diorite of, 33, 39. 
 
 HoUybush Pool, 35. 
 Hornblende schist, 29, 44, 46. 
 
 spongy, 39, 40. 
 
 HoENE, Dr. J., 58, 64. 
 Hornfelsing, 51, 56. 
 
 IsLA, RivEB, 2, 4, 6, 61, 72. 
 
 K 
 
 Keith, 10, 18, 22, 31, 44. 
 Kemp, J., 74. 
 Kidston, R., 58, 83. 
 King, J. Falconek, 74, 75. 
 Knockando, 24, 27, 70. 
 
 Laish of Mokay, 1, 7. 
 Lakes, 2. 
 
 Lagantoul Wells, 16. 
 Lamprophyre, 35, 41. 
 Limestone, 16-18, 20, 74. 
 
 petrography of, 47. 
 
 analyses of, 74, 75. 
 
 quarries, 18. 
 
 Loch Dallas, 2, 69. 
 
 Loch Noir, 2. 
 
 Loch Park, 17. 
 
 Lossie, River, 2, 27, 28, 71, 72. 
 
 M 
 
 Mackie, Dr., 28, 42, 51, 57, 66. 
 Mica- schists — 
 
 of Banffshire series, 21-23. 
 
 of Central Highland Series, 25-28. 
 
 Mineral wells, 79. 
 
 Moine schists, 10, 24-27, 46. 
 
 Moray, 1. 
 
 Moraines, 71. 
 
 Mulben, 19, 20, 21, 72. 
 
 Burn of, 13. 
 
 Mulderie, Hill of, 31. 
 Muscovite granite, 37. 
 
 N 
 
 Nether Cluny, 37. 
 Netherly, 33. 
 
 diorite of, 33, 38-41. 
 
 analyses of, 44. 
 
Index. 
 
 91 
 
 O 
 
 Old Red Sandstone, 10, 58-64. 
 
 ■ areas occupied by, 10. 
 
 classification of, 58. 
 
 denudation of, 4, 5. 
 
 outliers of, 61. 
 
 soil derived from, 7. 
 
 contemporaneous lava 
 
 of, 62. 
 
 Orcadian series, 58. 
 
 Upper, 62-64. 
 
 fossils from, 64. 
 
 Peach, C. W., 81. 
 Peat, 7, 72. 
 
 Pegmatite veins, 28, 32, 42. 
 Peridotite, 45. 
 Phyllites, 21-23. 
 
 petrograpliy of, 47, 48. 
 
 Plication of Moine schists, 24. 
 Pluscarden Abbey, 63, 64, 71. 
 Population, distribution of, 6-1 
 Pot-holes, 17. 
 Pre-glacial valleys, 4, 66, 68. 
 
 Q 
 
 QUAKKIBS — 
 
 gneiss, 32, 76.- 
 
 granite, 76. 
 
 limestone, 16-18. 
 
 ■ sandstone, 62, 75. 
 
 schist, 76. 
 
 slate, 75. 
 
 Quartzite, 3. 
 
 of the Banffshire series, 12-16. 
 
 evidence of unconformity of, 12. 
 
 conglomerate of, 16. 
 
 of the Central Highland series, 
 
 25-28. 
 Quartz-diorite, 37-39. 
 
 R 
 
 Raffokd, 1, 5, 10, 27, 65, 68. 
 Residual minerals, 24. 
 River systems, 1. 
 Roads and highways, 76. 
 Road metals, 76-78. 
 Rothes, 6, 10, 13, 72. 
 
 Burn of, 33, 38, 42. 
 
 Glen of, 3, 6, 28, 60, 72. 
 
 SoAAT Craig, 63. 
 
 list of fossils from, 64. 
 
 Scant Hill, 15. 
 Serpentine, 30, 34. 
 
 petrography of, 44, 45. 
 
 Schists — 
 
 black or graphitic, 19-21, 48. 
 
 mica, 21-23. 
 
 Moine, or Central Highland, 10, 
 
 24^27, 46. 
 Slates, 21-23, 75. 
 Soils, 7. 
 Spey, River — 
 
 drainage system of, 1. 
 
 deposits of, 72. 
 
 rock- sections of, 27. 
 
 Valley of, 4-6. 
 
 Stob Hill, 31, 33, 39. 
 Striated surfaces, 65. 
 Structure of area, 10. 
 Surface relief, 3-6. 
 Syenite, 38. 
 
 Taylor, J., 64. 
 
 Teall, J. J. H., 47, 49, 51, 53. 
 
 Terraces, 68-72. 
 
 Tervie Burn, 4, 20, 62. 
 
 Tininver Quarry, 17. 
 
 Tormore Burn, sections on, 25. 
 
 Traquair, Dr., 58, 64, 81, 83. 
 
 Treble Burn, 15, 16. 
 
 Tulchan Burn, sections on, 26. 
 
 U 
 
 Upper Old Red Sandstone, 62-64. 
 . fossils of, 64. 
 
 V 
 
 Valleys — 
 
 age of, 4^6. 
 
 pre-glacial, 4, 66, 68. 
 
 Valley of the Avon, 4. 
 
 Lossie, 5. 
 
 Spey, 4-6. 
 
 Veins — 
 
 calcite, 16, 17. 
 
 granite, 28, 32, 34, 42, 43. 
 
 pegmatite, 27, 42. 
 
 quartz, 13. 
 
 W 
 
 Wangie, Hill of the, 1, 4, 62. 
 Westerton, 63, 69. 
 
 Zoisite-granulite, 46. 
 

 '^\.