^prfl Wmwrjiitg jptatg THE GIFT OF ENGINEERING LIBRARY kJMSaV »• Chapter I. List of Formations occurring in Northumberland . . z Chapter II. The Lie of the Rocks .. .. .. .. 3 Chapter III. Recent and Sub-Recent Deposits .. .. 5 -Chapter IV. Drift Deposits .. .. .. „ 13 Chapter V. The Permian Rocks .. .- .. .. .. 17 Chapter VI. The Coal-Measures.. .- 20 .Chapter VII. The Gannister Series and Millstone Grit . . ... 30 Chapter VIII. The Carboniferous Limestone, or Bernician Series . . 32 Chapter IX. The Tuedian Beds .. .. .. ., .. 43 'Chapter X. The Silurian Rocks.. .- .. 46 Chapter XI. Igneous Rocks: Dykes .. -- .. .... ..47 Chapter XII. Igneous Rocks, continued : The Great Whin Sill .. 51 Chapter XIII. Igneous Rocks, concluded : The Cheviots .. 55 Chapter XIV. Materials for a Palaeontology of Northumberland . . 58 Index .. .. .. ... ., ... ., 73 OUTLINES GEOLOGY OF NORTHUMBERLAND. CHAPTER List of Formations occurring in Northumberland. Proceeding downwards in the geological scale — that is to say, from those deposits which are being formed at the present day Tinder our very eyes, gradually to those rocks the origin of which dates from the earliest times — these notes will be conveniently grouped under the following heads : — RECENT DEPOSITS (Or such as are still forming). Rainwash Alluvium Peat Blowing sand .. Tidal deposits .. Land and freshwater. Eolian. Marine and estuarine. SUB-RECENT DEPOSITS (Or such as are of the same character as the Recent Deposits, but are no longer forming). Old lake deposits \ Old river gravels and sands ... V Land and freshwater. Bripk-earths and clays J Raised beaches Eolian and marine. Outlines of the Kaims or Asar Moor gravels Moraine heaps Upper drift sands Upper drift gravels Reasserted boulder clay Upper boulder clay , Lower drift sands and gravels Lower boulder clay DRIFT DEPOSITS. Marine. -Glacial, land. ■ Glacial, marine, and freshwater. Magnesian limestone Marl slate Yellow sands PERMIAN. .'.. Marine. UPPER CARBONIFEROUS (Or Coal Measures). Coal-measures proper \ Gannister beds \ Marine, land, and freshwater. Millstone grit J LOWER CARBONIFEROUS (Or Carboniferous Limestone and Cakiferous Sandstone series). Bernician series Tuedian Marine, land, and freshwater. Clay-slate and grits Basalt (Dolerite). Diorite. Porphyritic traps. Felsites. SILURIAN. ... Marine. IGNEOUS ROCKS. Geology of Northumberland. CHAPTER II. The Lie of the Rocks. The General Geology of Northumberland is simple in its broad features. The beds, as a whole, slope to the sea, so that anyone travelling from the Coast to the Scottish Border, across the Country, would be always encountering older and older formations. As he trudged along he might gradually pass over Permian, Coal- measure, Millstone Grit, Carboniferous Limestone or Bernician, Tuedian, and Silurian rocks. The direction of this general dip lies between South-East and East, so that the strike, of the rocks runs, about South- West and North-East. But looked at more closely much of this simplicity of structure is found to be obscured. A few undulations in the strata have here and there altered their course, which has been still more largely interfered with by a few long lines of dislocation or faults. Then masses of igneous rocks have been injected through and amongst the originally undisturbed beds, sometimes shooting along the lines of dislocation and filling them, or squeezing in between the strata along the planes of bedding, or at other times rising bodily as great bosses of consolidated trap and heaving the deposits around them. From these various causes the aforesaid simple geological structure of the country has been modified not a little, and in order to arrive at a fair understanding of their effects it will perhaps be best to enumerate the principal dis- turbances in their chronological order. The first of which we have any record occurred before the deposition of the Carboniferous rocks, and probably when the sea far away was teeming with Upper Silurian life. The older muddy and sandy sea-bottoms of Lower Silurian age lay flat and undisturbed when the Cheviot volcanoes first began to emit the lavas which we now find hardened into ash and porphyrite. The older Silurians were tilted upon end by this — probably not all at once but by continually repeated uprisings. The Old Red Sandstone times supervened, apd the Cheviot traps were stony and cold as they are now, although still with a tendency to occasional movements, when towards the end of that period, the upturned edges of the Silurians having been planed down by denudation, the lowest Carboniferous deposits were gradually accumulated around the flanks of the old fire-hills, abrading their sides and incorporating their fragments with Silurian and Old 4 Outlines of the Red sands. So far as we know no important event took place during the leisurely deposition of the Carboniferous series which, as it accumulated, crept steadily up the sides of the Cheviot range, without however entirely covering it, until near the close of that age. Then there is reason to believe that Northumberland became once more a focus of volcanic agency. The old Cheviot centre heaved again, and brpke the beds around it in sundry places, causing dislocations or faults more or -less parallel to its contour, with smaller radiating ones in its immediate neighbour- hood. A great sheet of lava — now basalt— was injected between, and to some extent through, the Lower Carboniferous Beds, vSafhilsta few of the radiating faults or fissures already mentioned ~wef5~ fife4^dthjamilar lava, some spreading over the surface and others failing To~"Teaefe-it.- JThese events destroyed- ' greater degree than the more Northern. Two of these lines of dislocation were especially noticeable in their effects. One, With a varying shift, threw down the beds to the North of Newcastle, so that the Permian limestone was brought side by side with the Coal-measures far below. This is the Ninety-Fathom dyke, which runs from Cullercoats, by Denton, to Greenside and Whittonstall, often much exceeding ninety fathoms in throw, but dying away to nothing a little to the West of Minsteracres. The other fault takes up Jthe running, as it were, where the first leaves off, beginning as it does a little to the South of Corbridge, and running almost due West and parallel to the Tyne, right out of the County into Cumberland. This is the Stublick dyke. It throws the beds down to the North, so as to to bring the Coal- Geology of Northumberland. 5 Measures cheek by cheek with the base of the Millstone Grit ; but it has had another and still greater effect, for it forced the beds on its downthrow side to dip quite sharply towards itself. The result of this alteration of dip, both in amount and direction on the ^North side of the Stublick dyke has been two-fold — first it has (added to the long anticlinal axis already noticed) altered the strike for several miles from its course, so that all the beds as they approach the Corbridge fold from the North and East, instantly strike due West — and secondly it has allowed the- preservation on its Northern side of a number of small true Coal- Measure coal fields, which, owing to the high dip near the fault, comprise many more seams than their limited areas would lead one to suppose. As usual with large faults, these and others parallel to them are accompanied by a number of transverse or radiating dislocations, with minor throws. In later times, probably ranging to the Middle Tertiary, more faults were formed, but not of such importance, and these, together with older ones, were again filled with molten basalt from below. The above are the main disturbances recorded by the present geological structure of Northumberland where it is best known, but it^ must be confessed that several large faults in the north of the county are not yet sufficiently understood to be included in any general statement of this kind.* CHAPTER III. Recent and Sub-Recent Deposits. RAINWASH : — According as the various rocks forming the country axe more or less exposed to the effects of weather, and according as their texture and structure render them more or less liable to disintegration, solution, or splintering, so is the thickness of the deposij: or surface-accumulation known as rainwash. Many varieties of rainwash occur in Northumberland. Surfaces of true or re-assorted boulder clay, when exposed; — as in numberless railway cuttings — to the action of rain, become capped by a sandy and slightly gravelly rainwash, the clay being gradually washed away. Exposed sandstone districts, such as occur sparingly over the Coal-Measure areas, but very abundantly in the Western half and Northern parts of' the county, afford a * For instance, a great East and West Fault running from the Coast to a little to the South of Lowick appears to repeat the entire Bermcian Series. Other examples t times "scared" with coal, and they form conspicuous hummocky- hillocks on ground averaging from 300 to 500 feet above the level of the sea. The castellated " dovecot " to the West of Bavington Hall stands on one of a number of these kaim-looking mounds. Another is well shown near Chollerton on the Northern slope of the drift-filled Erring Burn valley. Along the Southern and South Eastern base of the Cheviot hills again these sand and gravel' " dodds," as they are sometimes called, can be seen. It may perhaps be urged that these gravels should be considered as the equivalents of the Drift sands and gravels which occur in the Boulder Clay and it must be admitted that were it not for the marked kaim-like forms which they assume there would be a good deal to say in favour of such a view which, indeed, may after all turn out to be the 'true one. For the present, perhaps it will be safer to keep these deposits distinct. Besides these doubtful accumulations, there are the great spreads of undoubted Upper Drift Gravels and Sands with occasional bands of unctuous clay, of which mention has been made before, when speaking of the river gravels. These are very largely distributed in-i Northumberland and fill most of the larger valleys. In that of the Aln they are strongly developed and also in the Wansbeck, the Tyne, and the Derwent valleys. In the last-named, some beautiful sections are to be seen,, especially by the river-side near Rowland's Gill, where the sands and gravels are well-shown resting on the Boulder Clay. This; is the case also near Mitford above Morpeth on the right bank of the Wansbeck. At Rothbury likewise they are seen in' abundance and, as Mr. Topley, F.G.S., has well remarked, the- difference between them and the porphyritic river-gravel now carried down by the Coquet is extremely obvious. Above Wylam, opposite. Corbridge, and at many other places in the- neighbourhood, the sands are predominant whereas up the South Tyne the gravels are more frequent. In the latter near Thorn- grafton striated pebbles (all of rocks foreign to the district) are- plentiful and would no doubt be found elsewhere if carefully sought for. These sands and gravels still fill up a great number of valleys of which we only become cognizant by workings and borings for coal. Most of the washes which sometimes interfere so greatly with winning the coal, causing great gaps where solid rock was expected are of this kind. Thus the Rev. Mr. Howchin has been able to surmise with great sagacity that a former connexion existed between the valleys of the Blyth and the Wansbeck. This case is not exactly analagous to that of the old Irthing- Valley discovered by Mr. Burns and already referred to. The Boulder Clay. — This has been often divided into Upper and! Geology of Northumberland. 1 7 Lower, and in some parts of England the division is undoubtedly a legitimate one, since there a great series of "middle sands and gravels " is seen to intervene. In Northumberland, however, the Boulder Clay is with a few exceptions, which can be regarded as exceptions only, a homogeneous mass of stiff brown to bluish clay laden with boulders of all sizes, limestone, sandstone, basalt, and porphyrite predominating — all rocks belonging to the surrounding district. Foreign rocks are usually present in the form of much smaller fragments. It may be stated that as a rule the upper portion of the Boulder Clay is freer from Boulders than the lower, and that, as has been noted before, sands and gravels (of no great thickness or continuity however) are sometimes found in the clay, occupying thus in a certain degree a position not unlike that of the middle sands and gravels mentioned above. The thickness of the Boulder Clay is extremely variable and its distribution is very wide. The entire coalfield may, speaking generally, be said to be covered with, it, and its limit of height to the West is vertically great, probably not far below 1,000 feet above the sea-level. That the Upper Drift sands were deposited upon the denuded surface of the Boulder clay seems abundantly proved. With one solitary exception no fossils have been found in the clay. In this case, as was to be expected, the shells found belonged to Arctic species long extinct in British Seas.* CHAPTER V. The Permian Rocks. Only three fragmentary patches of Permian rocks are left to attest the former presence of this series in Northumberland, * In a paper " On the Glaciation of the Counties of Durham and Northumber- land," by Mr. R. Howse, the following Schedule of the Superficial Deposits & adopted, viz. : — " z. Beds of peat, and submarine forests with fossil remains of oak, alder, mountain-birch, and hazel; horns of Ccrvus Akes and Ccrvus Elaphm, Bos primigenius, etc. " 2. Rubble transported from moraine heaps of upper valleys. "3. Gravel beds, forming remains of ancient raised beaches. " 4. Sand, forming elevated mounds along the courses of valleys. "5. Brick clay, with intercalations of laminated-clay, sand, and peat-bed con- taining skeleton of Megaceros Hibernicus, and stems of Calluna vulgaris. "6. ? Scandinavian drift, containing angular flints, and small fragments of rock, Srobably derived from boulder-clay. * der-clay or drifted glacier-moraine containing fragments of Cyprina Jslandica. "8. Ancient gravel, bed resting on rock-surface " : Transactions of the North of England Institute of Mining Engineers, Vol. xiii., 1863-64, p. 170. t8 Outlines of the namely at Tynemouth, Cullercoats and Whitley, and Seaton Sluice. That they formerly spread over a great portion of the County cannot be doubted, and it is instructive to note that the preservation of these small outliers is in each case due to accidental causes. Only the lower portions of the Permians occur in Northumberland, the sub-divisions left being as follows : Magnesian Limestone. — Of the great Magnesian Limestone as it is seen in the County of Durham the Middle and Lower divisions only form part of the Permian patch at Tynemouth. The Middle Limestone, being the highest number of the series present, is here very much denuded. It is very difficult of access, but a number of fossils are recorded as coming from this locality, the shell-limestpne, so-called from being the most fossiliferous portion of the Magnesian Limestone, belonging to this division, which is also called the cellular limestone. The deposit (as a whole) is thus described by Mr. Howse* : " An amorphous irregular deposit of highly crystalline or saccharine limestone, occasionally full of small, irregular cavities, partially or entirely filled with a fine earthy powdery substance ; other parts present the appearance of being formed of shapeless fragments of compact limestone imbedded in a completely investing matrix, without taking the form of a true breccia." Below this limestone lies the Lower division well-known at Tynemouth and at Whitley Quarries to the West of Cullercoats, where the Permians have been thrown down to the North by the great fault known as the " Ninety Fathom dyke." This consists of compact limestone passing locally into a conglomerate. The thickness of the Lower Magnesian limestone is given as 150 to zoo feet.f Fossils similar to those of the Middle division, but not so abundant, are recorded from these beds. At the Whitley Quarries, now used as a reservoir by the North Shields Water Company, the limestone may be well studied, but neither its tops nor its base can now be seen. Marl Slate.— -A thin yellowish set of finely laminated beds known by the name of marl-slate comes next in descending order. It is seen skirting the rock on which Tynemouth Priory , is built, but it is practically inaccessible there. At Cullercoats it can be found, at very low water only, near the end of the southern break-water in course of erection in the little fishing harbour. In the Whitley Quarries it has been reached by.a little sinking. The marl-slate although only about three feet thick is remark- , able as having yielded a very fine series of fossil fishes in a * "Notes on the Permian System of Northumberland and Durham": Trans. , Tyne. Nat. Field Club. Newcastle, 1858, p. 4. t Lac. «'(., p. 5. Geology of Northumberland. 19 beautiful state of preservation. Although at Cullercoats the bed is, with the rest of the rocks, thrown down by the Ninety Fathom Dyke, yet it would be entirely hidden from view were it not for another fault, a small one, running parallel to the great dislocation and which directly affects the fish-hed. Owing to this lucky condition of things frequent finds of splendid fish remains have been rendered possible. Yellow Sands and Lower Red Sandstone. — Below the Marl Slate comes a very peculiar rock known as the Yellow Sands, the characters of which are very striking. It consists of a very coarse grit made up of perfectly rounded grains of quartz cemented by Carboriate of Lime. The grains are so loosely held together that they crumble away to the touch and that hand-specimens can with difficulty be earned away entire. This grit is very strongly false-bedded and is cut through and through by a tangled net- work of vein-looking lines of closer cementation which stand out in the shape of ribs or ridges from the weathered surface of the rock. In places these ribs, probably from some form of incipient segregation in the Carbonate of Lime, weather into small spheroidal masses. These various aspects of the rocks are very beautifully displayed in the cliff just South of the Baths, at Cullercoats. No fossils are known in this singular rock. Below these " Yellow Sands " and usually grouped with them comes the lowest division of the Permian Series. This bed or set of beds consists of reddish sandstone, including fragments of various coloured shale, and yielding an assemblage of fossil plants -belonging to Coal Measure species. It has been proposed on this account to unite this rock with the Coal Measures, and thus to regard it as Carboniferous instead of Permian. Sir Roderick Murchison, Mr. Kirkby, and others, have however shown very sufficiently that this view was opposed to the numerous and weighty facts which show the Yellow Sands at least to form a part of the Permian system. The base of the Permian rocks lies unconformably upon the Coal-Measures in Northumberland, as indeed it generally does throughout Britain. In other words, the lowest Permian beds were deposited after the Carboniferous rocks had been denuded, and after their originally horizontal — or nearly horizontal — position had been disturbed and to some extent altered by move- ments long subsequent to their deposition. This unconformity is well seen at Tynemotlth, but not at Cullercoats. At the third point, however, on the coast at Seaton Sluice, near Hartley, it is very well proved. Here a very small but unmisitakeable patch of Lower Permian has been preserved by the aid of a slightly basin-shaped' hollow on the surface of the Coal-Measures, assisted also by a small fault. No great pritai 20 Outlines of the facie evidence of discordant stratification is shown here, but the fact that the horizon of the Coal-Measure beds underlying the Permian at Seaton Sluice is not that of the beds underlying the Permian at Cullercoats or Tynemouth, conclusively proves the real unconformity. In this way the tiny mass of sandstone which denudation has spared at Hartley is very useful to the geologist. The late Mr. W. Hutton discovered and described a small patch of what is considered to be Lower Permian on the North or downward side of the Ninety Fathom Dyke near Closing Hill, a small eminence rising from the Boulder Clay a little to the South of Killingworth House.' Little, however, can now be seen there either to confirm or throw doubt on this view.* CHAPTER VI. The Coal-Measures. After what has been said at the end of last chapter respecting the unconformity of the Permian upon the Carboniferous rocks it will be evident that we could scarcely expect to find the uppermost beds of the Coal-Measures in Northumberland. As a matter of fact, these beds^ are not present, and, although we have some two thousand feet of rock belonging to this division, we are unable to say how much more was denuded away before the deposition of the Yellow Sands. In other Coal-fields the Coal-Measures are often divided into Upper, Middle, and Lower. This has been attempted in this district, but owing to the facts just stated, there are many objections to this mode of procedure. I have therefore adopted a plan which I elsewhere proposed ;\ namely, that all "the beds from the highest-known in the Coal- Measures in the district down to the Brockwell Coal inclusive — that is to say, all that series which contains the best coal-seams — should be called " Coal-Measures " simply, without further sub- division, and that the beds below the Brockwell, and as far down as the top of the first important and recognizable band of lime- stone of the Carboniferous Limestone Series, should be grouped together as the " Gannister and Millstone Grit Series." This is the arrangement followed here. Speaking lithologically, and in the order of prevalence, the Coal-Measures of Northumberland consist of alternating beds of * Trans. Nat. His. Society Northum. and Dur., Vol. i. (1831), p. 72. •i Trans. N. Engl. Inst. Min. Mech. Engineers, Vol. xzv., 1876. Geology of Northumberland. 2 1 Sandstone, Shale, Fire-Clay, and Coal, the chief characteristics of which may now be given.* Shales. — The shales of the Coal-Measures are not distinguish- able lithologically from those of the other divisions of the Carbon- iferous rocks of the County, save that they are but rarely calcareous ■(seldom yielding more than 2 per cent, of lime, according to published analyses, and usually far less) and are more frequently bituminous. The number of varieties is very great, and a series can easily be arranged showing a perfect gradation from splint coal on the one hand, through bituminous shale (or black shale), non-bituminous shale (blue shale), grey shale, micaceous shale, and arenaceous shale, to true sandstone on the other. Locally, shale is called Plate or Metal, and the convenient term Grey Beds is used to denote the many-bedded alternations of sandy shales and shaly sandstones, generally micaceous, which form much of the main bulk of the Upper Carboniferous Series. Many of these shales contain nodules and continuous bands of clay-ironstone, some of which have been worked from time to time, but cannot now be said to be remunerative under ordinary circumstances. Some of the continuous ironstones will be referred to presently under the heading of " Mussel Bands." It is common for the larger coal seams to be covered by black shale, and some theories concerning the origin of coal have been based on a hasty assumption that this was always the case. It is not so, and many cases can be adduced where in this coal-field the coal is succeeded by grit and, in the Lower Carboniferous, by limestone. When, however, shales cap the seams, they are often very rich in vegetable remains, and it is this that calls our attention more particularly to these ancient compressed mud- beds. Ferns, Calamites (ancient Equisetce or Mares' tails), Lepidodendra (allied to our Club-mosses), and conifers, abound with other less well-defined forms in many of these shales, more especially in the least micaceous or sandy varieties. Naturally enough the fossil contents of thdse beds are best known that are associated with the more commonly worked coal-seams. Thus the plants of the High-Main, the Bensham, and the Low-Main Shales have long been collected and described, whereas, unfortu- nately, other horizons, very likely as rich and interesting, are still undiscovered or but little known. But besides plants, some of these shales have proved extremely prolific in the remains of fishes and saurians. * The North of England Institution of Mining and Mechanical Engineers have just issued (1878) the first volume of an almost complete collection of all the measured sections and borings in Northumberland and Durham. ' The collection, when the "whole is published, will render it possible to sectionize the coal-field in a manner quite unequalled in any other part of the world. 22 Outlines of the It is mainly owing to the unwearied industry of one man, Mr Thomas Atthey, A.L.S., of Gosforth, that we are enabled to view side by side, and in a remarkably complete manner, the fauna and flora of one great horizon in our Coal-Measures. The animal and vegetable life which thronged East Northumberland shortly after the deposition of what we now call the Low Main Coal is better known to us than that of many parts of the living world. A portion of the shale overlying this seam is a true fish-bed, the minute searching of which has been a labour of love to Mr. Atthey for many years, and from which an unequalled collection of fish and amphibian remains has been obtained. * These fishes, as will be seen by the lists 1 at the end of the volume, all belong to species which lived, probably, in fresh or merely brackish water, no evidence of marine conditions being therefore forthcoming from this source. The locality whence most of these specimens come is Newsham, near Blyth, but the fish-bed appears to be very constant, and has been recognized in various other parts of the field, and in Durham. Mussel Bands. — Geologically perhaps the most interesting beds in the Coal-Measures of this district are the thin deposits known as Mussel Bands'. These are bands seldom more than a few inches in thickness, consisting almost entirely of the shells of Anthracosia — a genus of molluscs allied to the mussels of our rivers, and supposed (although not on perfectly conclusive evidence) to be, like them, strictly of fresh water habit. Along with the shells bits of drifted wood belonging to common Carboni- ferous forms, and impressions of ferns, are occasionally found. These little shell-beds contain usually a considerable per-centage of iron ; in certain cases sufficient to allow of their being worked as ironstone. The following analysis of one of the best known and most persistent of these bands is given by Messrs. Clapham and Daglish + :--— Sol. in Acid. Insol. in Acid. Silica trace 31*068 Alumina i'i94 16-292 Lime 4:084 •. 0*988 Magnesia 1-078 0*288 Potash i.'3i9 — Sulphate of Soda trace — Protoxide of Iron 18*637 — Water of combination 11*221 — Carbonic Acid 14*057 — 5 1 "590 48-636 * This collection has been recently acquired by the Natural History Society or. Northumberland and Durham, in whose museum it now lies. t Trans. N. England Institute of Min. Engineers, Vol. xiii. (1S63-64), p. 221. Geology of Northumberland. 23 The horizon of this mussel-bed is a few feet above the Low Main Seam ; another equally constant zone of this kind occurs in connexion with and above the High Main Coal. Altogether, not more than six Anthracosia bands are known in the Coal-field, and of these the exact position of two is doubtful. At Whitley, at the base of the cliff, the shell-bed can be very well seen in places at low water, and the old shale-heaps above abound in excellent well-weathered specimens. In the cliff near Hartley there is also a good exposure of the kind. One of the highest shell-beds of the Coal-field has, in Durham, at Ryhope, yielded a marine shell (or, at all events, one belong- ing to a genus which, although known to be sometimes estuarine, has no claim to be regarded, as' fresh-water,) viz., Lingula mytiloides. No example of the kind has yet been recorded from Northumberland from any horizon above the Gannister Beds (Lower Coal-Measures of authors.) Sandstones. — The Grits and Sandstones of the Coal-Measures are, as a rule, fine-grained and of a greyish or yellowish colour, but, in truth, they can scarcely be said to have any special character which they do not share with the arenaceous beds of the older members of the Carboniferous Series. There is always iron present in appreciable quantities, the per-centage of oxide of iron being sometimes as high as 10 and seldom lower than 1, the average being about 5. It may be noted that the dark colour of the rock is by no means a sure test to apply in estimating the amount of iron present, the grey sandstones usually containing more than the brown ; the white beds being,! however, very poor in that substance. The richest are, generally speaking, the micaceous varieties. Messrs. Clapham and Daglish* remark that " the chief characteristics of the sandstones seem to be the quantity of iron, lime [very 'rarely exceeding or even reaching 3 per cent, however] , or magnesia they .contain, which is the cause of their decomposition when exposed to the action of disintegrating agents." There is in most of these beds a tendency to segregation of colouring matter in the form of. concentric bands of various tints, sometimes giving rise, after long exposure to the air, to singular variegated effects. This is well-shown in many of the dressed- stone buildings of Newcastle and Gateshead. The concretionary action is often accompanied by exfoliation and disintegration. The thick sandstone known locally as the Grindstone Sill or Post, whence the celebrated Newcastle grindstones are cut, exemplifies the above remarks. It is on the whole a fine-grained moderately hard light-yellow stone, but it is in places soft enough * Loc. cit.,p.?2i. 24 - Outlines of the for the manufacture of filter stones, which were formerly exten- sively made from it,* and its upper part is often " abundantly impregnated with yellow ochre, which is sold under the name of die-sand." The chief heights of Newcastle are formed of this bed, as at Byker, Benwell Hill (Condercum), Kenton, etc. The Burradon fire-stone, near Killingworth, belongs to the same deposit-! It will be seen that variation is common with these sandstones, and this is the case not only in composition, but also, and still more markedly, in thickness. In the excellent Coast-sections between Seaton Sluice and St. Mary's Island instances of very rapid thinning and thickening on the part of both sandstones and shales are frequent, and again in the rocky cliffs between Whitley and Cullercoats. How variously these changes affect the dips of the beds locally seems very obvious, but, strange to say, this appears to be by no means universally understood.]: There does hot appear to be any noticeable change in the general character of the sandstone beds from the highest to the Brockwell seam, unless it be perhaps that in the lower ones nests of well-formed quartz-crystals are commoner, as is the case in the district between Wylam and the Derwent: l In all, or nearly all, the remains of plants are common, Sigillarian stems predominating, but Lepidodendra, and Cala- mites often occurring also as casts more or less coated with carbonaceous matter. Many of the finest fossils of this descrip- tion have been found in one or other of the numerous quarries in the outskirts of Newcastle, some indeed having acquired a more than local celebrity, such as the once well-known Wide-Open tree, from Wide Open Quarry, between Seaton Burn and Gosforth. Fire-Clays. — Generally forming the floor of Coal-seams, but occasionally unconnected with , them, we find throughout the Coal-Measures a number of deposits of Siliceous clay known as tmder-clay, Seggar-clay, or Thill, and often used as fire-clay. These deposits are common to all Coal-producing districts. They are the impermeable clay-bottoms which allowed the swamp- vegetation of the Coal to flourish, and we may with propriety liken them to the clayey marls which we find supporting the growing peat of our bogs. * N. J. Winch, Transactions of -£he Geological Society, Vol. iv., p. 17., 1816. + The sandstones, enumerated here all belong to one series overlying the High Main Coal, and subdivided locally as follows, in ascending order: — 1. Main or High Main Post. 2. 70-fathom Post, in one, two, or three members parted by very variable shales. 3. the Grindstone Post. Post is the local term for sandstone but is applied also to any distinct massive bed, thus a " post of limestone " is often spoken ofT } See W. Topley, F.G.S., " On the Correspondence between some Areas of apparent Upheaval and the Thickening of Subjacent Beds." Quarterly Journal of the Geological Society, Vol. xxx. (1874), p. 186. Geology of Northumberland. 25 These Seggar-clays are as a rule full of the large roots of Sigillarian plants known as Stigmaria, and more especially of the long leaf-like rootlets springing from them. The association of the Coal and its under-clay, and that of Sigillaria with Stigmaria are themes always dwelt on at length in elementary text-books of Geology. They are now well understood, and need not, therefore, detain us here. Almost every Seggar is more or ltess of a fire-clay, the best adapted for refractory purposes containing a large amount of silica, and being comparatively free from lime, iron, and other impurities. The following analysis of a local under-clay is given amongst others by Mr. Joseph Cowen, M.P., and is quoted- here on account of the unusually large percentage of silica : — Silica.... 83*39 Alumina 8"io Iron and lime 2-43 Magnesia 2*99 Water and organic matter 3-64 100*45* Coals. — Owing to the varying thickness of the sandstones and shales intervening between the Coal-seams, to the inconsistent and ever-varying nomenclature of the latter, to the numerous intersecting faults, and — more than all the rest — to the thick covering of Drift which obscures the greater portion of its area, it was long before the structure of the Coal-field was well under; stood. In 1814, Mr. Winch thus spoke on the subject: " It is not possible to discover in the Coal-measures any regular order of succession, which will apply to the whole Coal-field, and it is even with difficulty that in very limited portions of it the continuity of particular seams can be traced. . This arises from the variable thickness and the rapid enlargement and contraction of the different beds; that which in one section is scarcely perceptible, having attained in a neighbouring pit the thickness of several fathoms " " It is useless, therefore, to attempt any general section of the Coal formation." f The late Mr. Buddie was the first to bring order into the "apparent chaos thus described. In his luminous "Synopsis of the seams of Coal in the Newcastle district," read in 1830 before the Natural History Society of Northumberland, he laid the foundation of all that has since been done in unravelling the .geological features of the district. In a masterly manner he * " Industrial Resources of the Tyne, Wear, and Tees." Ed. 2 (1864), p. 207. t Trans. Geol. Soc. Vol. iv., pp. 12, 13. (1816). 26 Outlines of the seized the main features of the lie of the beds, and described them so thoroughly and clearly that since his time it is only in matters of detail that his synopsis has been found wanting.* Taking the best-known coals only, and following in the main the views of Mr. J. B. Simpson, F.G.S., + as the latest and most exact exponent of the series first tabulated by Buddie, we have the following seams in the Coal-Measures from the highest-known in the County to the Brockwell. COAL SEAMS. 21. Closing Described by the late Mr.- W. Hutton, on the Hill authority of the late Mr. N. Wood, as cropping out Seam, on the N. or downthrow side of the Ninety-Fathom dyke, in a quany about 950 yards from Killingworth House. The seam was '20 inches thick, and is worth noting since it is quite the highest recorded in the district, being, according to Mr. Hutton, at least 450 feet above the next-mentioned coal, which is usually looked upon as the highest. From its position the area of this seam is necessarily limited in extent to the immediate neighbourhood of the spot noted. •Very little is known of this coal, which may possibly be the same as the highest met with in the Boldon Colliery pit on the South or Durham side of the Tynei near Brockley Whins. Strata: About 450 feet, ao. Hebburn Fell, About 2 feet ,8 inches thick. It extends over or Monkton Seam, a very limited tract of country, and is of inferior quality. Strata : About 250 feet. 19. Five-Quarter About 4 feet thick. Well-known in Durham Seam. but doubtful in Northumberland. Probably the highest thick seam in the North Seaton Section. (Not to be mistaken for the lower Five-Quarter seams.) Strata .- About 260 feet. 18. Three-Quarter, \ %%££% ' About 3 feet thick, often less. or jo-Fathom Coal. J Strata: Very variable, 50 to 180 feet. 17. High Main, About six feet thick. This seam is often taken or Main, as the boundary between the Upper and Middle or Seven-Quarter, Coal-Measures ; a view that I cannot agree with. or Glebe Coal. That it is in a sense a natural limit of some * Trans. Northumb. Nat. Hist. Soc. Vol. i., pp. 215-240 (1831). t See the Sheet of Sections recently published by Mr. J. B. Simpson, and entitled " The Coal Seams of the Northumberland and Durham Coal-field," 1877. Geology of Northumberland. 27 kind cannot be denied since it separates a series of thick and tolerably constant Sandstones above it (including the Grindstone and 70-fathom posts)- from the rest of the Coal-Measures. Formerly it was the most valuable seam in the Coal-field, but is now almost entirely worked or burned out. Between the Tyne and the Ninety-Fathom Dyke the coal was at its best, but it also underlies a considerable extent of country to the North, between Denton and the mouth of the Wansbeck. It is- the type " Wallsend " household coal. Strata : — Very variable, seldom more than 150 feet. 16. Metal Coal. Strata: — 33 feet. 15. Stone Coal. These two seams are ► or Grey Seam, separate on the Tyne, and continue so for some distance to the North and East, but to the North and West they coalesce and form what is known as the Grey Seam, a coal which attains a thickness of nearly eight feet at Cramlington. The Metal and Stone Coal unite again in Durham where, together, they are called the " Five- Quarter Seam." Strata : — Variable, 60 to no feet thick. 14. Yard Coal. About two feet 10 inches to four feet thick. Above this seam is a shale in which fish remains are found. Strata : — 60 to 100 feet thick. 13. Bensham Seam. Two feet five inches to five feet thick. This is the Maudlin Seam cf Durham. Strata : — About 75 feet, with thick sandstone at base. These seams are ■ Five Quarter Seam, sometimes known as the Tyne Six-Quar- ter and Tyne Five- Quarter Seams. They are distinct in the Eastern parts of the field, but coalesce towards the West of the Steam Coal district. Strata : — About 50 feet. 10. Low Main, or Variable in Northumberland from 2 feet or Hutton Seam, less to 6 feet. It is the ' Hutton Seam of Durham. For many years this was the owest seam sunk to below Newcastle. This Coal-seam " is not only continuous throughout the whole extent of the Coal-field, from Warkworth, in the North, to Haswell and Hetton in the South (nearly the Southernmost extremity of the Coal-field), but .... it also yields the best description' of three different varieties of coal, suitable for purposes not at all similar to each 13. Silf-Quarter Seam, Strata : — 35 feet. 11. Five-Quarter Seam., 28 Outlines of the other, viz. : the best household [in Durham] , the best gas, and the best steam coal [in Northumberland] ."* Strata : — Variable, from 30 to 100 feet. •g. Plessey, of Crow, A variable and inconstant seam, best or Ryton Ruler Seam (?) developed in the Morpeth district, where it is known as the Plessey seam. It is with diffidence that it is here correlated with the seam called the Ryton Ruler in the Blaydon district. Its thickness is usually less than 3 feet. Strata: — Variable, about 80 to 150 feet. 8. Beaumont, About a yard in thickness. It is called the or Towneley, Beaumont in the Morpeth district? the Towneley or Harvey Seam, in the Blaydon district, and the Harvey in Durham. Strata : — About 20 feet. 7. Hodge Seam. About two feet four inches. Only known in the Elswick and Towneley district. Strata : — About 20 feet, sometimes more ■6. Tilley Seam. From two to three feet thick. Occurs in the same district as the Hodge Seam. Strata': — From 30 to 45 feet, comprising in the upper part the 5. Hand Seam. A thin (four inches), but well-known seam, in the Towneley district. 4 Stone Coal. \ Two seams occur- Strata : — 25 feet. [■ or Busty Bank Seam, ring apparently only 3 Five-Quarter Coal.) in the southernmost parts of the North- umberland Coal-field, in the outliers of Whittonstall, etc. . . . but well known on the Derwent, where they unite (as at Medomsley) to form the Busty Bank Seam, about six feet thick. The Five-Quarter Seam is sometimes known as the Six-Quarter Coal in the Wylam district. Strata-: About 30 to 50 feet (rarely so thick). 2. Three-Quarter Coal, About a yard thick. Best known between or Yard Seam. Wylam and Wolsington. Strata : About 50 feet, variable. 1. Brockwell, From 1 foot to 4 feet thick. Has been looked or Splint Coal, upon usually as the base of the Coal-Measures, or Main Seam, but has been taken by the Government Geological Survey as the Boundary line between the Middle and Lower Coal-Measures or Gannister Beds. It appears to be * " Industrial Resources of the Tyne, Wear, and Tees." Ed. a, (1864), p. 13. Geology of Northumberland. 2 9. fairly constant throughout the district, but this may be owing, to- some extent, to the fact that the lowest workable seam of any district is ipso facto called the " Brockwell." Besides the above twenty-one principal seams there are a great number of minor beds of Coal which it would serve no good purpose to enumerate. Although occasionally sufficiently thick to be profitably worked, they are not so, as a rule, and are for the most part very incompact. Mr. T. Y. Hall, in 1854, stated the seams then known in the Coal-field as fifty-seven. Owing to the increased borings and sinkings since that date that number is now very much greater. A glance at a modern geological map of Northumberland will show that beyond the regular Coal-field extending from the Coquet to the Tyne there is a line of small detached semi-basins of Coal-Measures stretching from the main mass to Westward beyond the County boundary into Cumberland. This extension of the Coal-Measures was first pointed out by Mr. Nicholas Wood in 1831 in a remarkable paper, which — with Buddie's synopsis — may be said to have done more for the advancement of North- umbrian Geology than any two memoirs written before or since.* A reference to our Chapter on the Lie of the Rocks (p. 4) will show that two causes have united to bring about this arrangement,, viz. : first, the general flatness of the beds West of the long Corbridge fold; and second, the disturbance of that flatness by the great Stublick Dyke. It will be seen that most of these little Westerri Coal-fields lie on the downthrow side of that dyke, and that one or two less important ones are similarly placed as regards the Western or dying-out portion of the Ninety-Fathom Dyke. Although by far the most important of the rock-divisions of Northumberland, it will be noticed that beyond matters of detail there is but little complexity in the Coal-Measures as there developed. From Acklington, where the Northernmost outcrops, are worked, and where the correlation of the Coals is not a little doubtful, through Widdrington, Woodhorn, etc., to the well-known old pit sections on the Tyne, we find (faults being left out of consideration) scarcely any change of importance affecting the series : local variations in thickness here, the splitting up, of seams there, and similar accidents, although of much interest commercially, being, in regard to the distance involved, extremely small matters, geologically speaking. The changes that do occur are such as are common in all Coal-fields, and can all be referred to the normal conditions under which coal-bearing strata were deposited. We sometimes * Trans. Nat. Hist. Soc. Northumberland. Vol, i. (1831), p. 302, ^o Outlines of the hear of the " swellies," or local thickenings of coal, along lines of depression — ancient Coal-Measure miniature valleys in fact — as wonderful accidents. A little reflection will show that old land- surfaces, such as our coal floors tmce were, need not, according to any known law, have been of perfectly uniform level — a walk over a modern Peat-moss or swamp will show that Peat has its "swellies" as well as coal — and that we must not wonder, but observe. But if such " accidents " are to be expected, they are none the less interesting on that account. The well-known "swelly" of the Low Main Seam, which Mr. Hurst has described with such minuteness and care,* is an excellent example of this heaping up of Coal-matters owing to the form of the floor or thill, and full descriptions of other cases are much to be •desired. Other minor disturbing elements in the continuity of the seams are so called " stone-dykes," which are frequent in many collieries. These are merely ancient " washes," in every respect to be compared to the washes of sub-recent deposits which we have already spoken of, and from which they differ only in having filled up the valley cutting through the denuded seam, in Carboniferous times, before or during the deposition of the over- lying beds. By mapping out the courses of swellies and " stone- dykes " we arrive at a general notion of the small features which alone seem to have broken the monotonous uniformity of the ancient flats on which the* coal vegetation grew. • CHAPTER VII. The'Gannister and Millstone Grit Series. The rocks which in Lancashire and Yorkshire are conspicuous under these names are in Northumberland in nowise distinguished from the Coal-Measures proper, of which, indeed, they are simply the continuation. They comprise all those beds which lie between the Brockwell Seam and the Felltop Limestone, and like the great Series described in the, last chapter, consist of sand- stones, shales, and coals. The last, as a rule, are thin and seldom workable. They appear, indeed, to be much less constant than is the case with the larger seams above, but not less so than the smaller ones, to which alone they should properly be compared. The name Gannister is given to the upper portion of this •division on the assumption that the beds comprised in it are the Trans. N.' Engl. Inst. Min. Eng. Vol. viii. (i860), p. 23. Geology of Northumberland. 3 1 •continuation or true equivalents of the well-known Gannister- bearing rocks farther south. Gannister is a local term applied to an extremely hard and very fine-grained, compact, siliceous kind of underclay usually pierced through and through by a great number of fossil rootlets (stigmarian), and valuable for refractory purposes. Now, the presence of stone answering this description in a greater or less degree in Northumberland (as at Saltwick to South of Morpeth, and at several places to the South of Stocks- field) somewhere about the horizon at which it occurs in other districts (although the parallelism has been more than once questioned), lends force to the view that we have here, in truth, the representative of the true Gannister Series, or Lower Coal- Measures. This has been further favoured by the discovery, which I had the pleasure of making early in the present year, of a few marine fossils — including Aviculopecten papyraceus, the Gannister fossil pay excellence — in these beds near Whittonstall.* With regard to the Millstone Grit there is no reason to doubt that what is known by that term here is really the representative, or in part the representative, of the Millstone Grit which caps Ingleborough, Kinderscout, and so many others of the great Carboniferous hills further South. In short, " in Northumberland the place where the Millstone Grit should be undoubtedly exists, but the grits themselves are sadly deficient both in character and thickness. Shales, shaly sandstones, and sandy shales, with a few beds of sandstones, seldom coarser in grain than many beds in the Coal Measures, ■and not nearly so coarse nor so thick as some of the grits of the limestone series below — these, in considerable spreads between the Derwent and the Tyne, and in a, narrow band from the latter river to the sea near Warkworth, are the component parts of the Northumbrian Millstone Grit. This miserable representative of the great hill-capping deppsit further South would never have been recognized as a chief division here had Northumberland been an island, and had not the traditions of its greatness come from elsewhere. In fact it may be affirmed that the Millstone Grit has, as it were, traded on its thickness. In Northumberland it is thin where it enters the county to the South, and it is much thinner where it leaves it on the East Coast; it has here no lithological character which it does not share with members of the series above and below ; it has no distinctive fossil remains ; in short, it has nothing peculiar to it but its position."f As I have stated already, there are some thin coal seams in hoth the Gannister series and Millstone Grit, and some of them * See " Nature" for February, and the Geological Magazine for March, 1878. t Trans. North. Engl. Inst of Min. Engineers, Vol. xxv., 1876, p. 227. 32 Outlines of the have from time to time been worked. A small colliery is, or was very recently, open to the South of Harlow Hill (on the Roman Wall) on the road to Ovingham, the coal worked being called the "Crankey" seam, and looked upon generally as the Brockwelf coal. It is however really one of the seams in the Millstone Grit series. At Harlow Hill, the lowest bed of this set of rocks, a thick massive yellow sandstone flecked with rust-spots is seen to rest on what is probably the finest exposure of the Felltop Limestone. As a consequence of the small importance of the coal-seams known to exist in the Gannister beds, not many detailed sections of sinkings or borings can be referred to for details of the strata. One of the few known is a boring which was made many years ago in Chopwell woods, on the Northern slope of the Derwent Valley, where a constant alternation of thin sandstones and shales, with worthless seams of coal in tolerable quantity, was proved to a depth of nearly 300 feet beneath the Brockwell coal. For many years a bed of ironstone was wrought in the upper portion of the Gannister series in the Derwent district. It was known as the "German Band"— a grotesque name due, not to any covert allusion to itinerant musicians, but to the small colony of German sword-makers who in former days worked this iron- stone and plied their trade at Derwentcote. The Millstone Grit beds are well seen at Warkworth, where the Coquet valley exposes fine sections of thenu The Wansbeck valley likewise displays them fairly well about Mitford, a little above Morpeth. They are, however, best seen in the* country lying between the Derwent and the Tyne, where, owing to the small amount of dip, they occur in wide spreads and outliers. To the North of Blanchland they can be well studied, as regards their relations to the Limestone Series below, the upper portion of which only occurs there. CHAPTER VIII, The Bernician Rocks. The chief peculiarity of the " Bernicians " may be said to be that representing as they do a number of divisions, which, in other parts of Britain and on the Continent, are well and clearly defined, yet they cannot themselves be divided at all in any natural manner. Geology of Northumberland. 33 The series consists essentially of numerous beds of limestone, of which the thickest seldom exceed thirty feet in thickness, of .grits and sandstones of every texture from that of the coarsest .grit to that of the finest-grained flagstone, of shales of every •character, and of coals with and without underclays in every way comparable, except as to commercial importance, with those •of the Upper Carboniferous Series. All these beds alternate rapidly so that a complete list' of them, bed by bed, if it could be accurately drawn up, would be of exceedingly great length. Moreover the value of such a detailed vertical section would be much lessened by the fact that it would only be true for the particular line along which it was measured. The thickness of the beds varies extremely from place to place, and many of them are of local occurrence only, and are frequently found to thin away and disappear very rapidly. Nor is it only the individual beds making up the series which alter so constantly in thickness, but the set of them as a whole undergoes very remarkable changes in this respect. First, then, as to the latter point. The entire thickness of the series in the Alston Moor district, which can very fairly be taken as the extreme South of Northumberland, was measured by Westgarth Forster as being about 2,500 feet; in the North of the County (the Alnwick and Scremerston district) about the same was the thickness estimated by the late Mr. G. Tate ; whilst between these two regions, in the tract lying between the Tyne and the Coquet, the maximum thickness attained is at least -8,000 feet. This fact — this thickening of the Lower Carboniferous rocks in the centre of Northumberland, when once known, gives a clue to the geological structure of the County which is of great value.* As to the changes in individual beds, it would be quite out of place to give full details of such facts in a general sketch like the present, but the following truths will be confirmed by all ■careful observers. J Having regard to the thick limestones bf Derbyshire — the " Mountain" Limestone properly so-called — and the thin and rare calcareous beds contained by the Series in Scotland, it might very reasonably be supposed that the Berni- cians, offering as they do a passage from the one form or "facies" to the other, would be marked by a regular thinning and dying' •out of it's beds of limestone. This is only partially the truth, however, for a close examination of the Series will show that although many of these beds in their trend from South to North do thin out and occasionally disappear, yet many of them main- tain and even increase their thickness. Not only that, but many * See Westgarth Forster's "Section 1 of' the Strata," 1829. Also G. Tate's "History of Alnwick," 1867, and G. A. Lebour "On the larger Divisions of the •Carboniferous Rocks in Northumberland," Trans. R^in. Inst. 1876. 34 Outlines of the new limestones make their appearance. This last is a point of some importance, and is more particularly illustrated in the area of greatest total thickness already referred to. Nor are the lime- stones alone affected in this manner; the grits are in a very marked degree inconstant, thick crag-makmg beds in a short space dwindling away to nothing, and being replaced by shales of equally uncertain continuity. The coal-seams likewise exhibit a much greater tendency to split up, thicken, and thin out in short distances, than they do in the Coal-Measures. So much for the general characters of the Bernician Series. Its most marked stratigraphical features may now be considered, in descending order. The top-most bed of the Series is known as the Felltop lime- stone, a name which is also given, unfortunately, to one or two , occasional thin and impure limestones which sometimes occur above it, in what, according to the classification here followed, is. the base of the Millstone Grit. It is not often well-exposed,, especially in the district South of the South Tyne, but from the Tyne to the Wansbeck it is in some places quarried and capitally seen. At Harlow Hill in particular, in a quarry to the South of the Roman road, it is beautifully exhibited. This section has been admirably described by Mr. Tate in his " Geology of the Roman Wall," published with Dr. Bruce's large work. Between the " Felltop " and the " Little '" Limestone in the Alston District is a thickness of some 350 feet of shales and sandstones with no limestones. This interval in the Matfen and Inghoe district (North of the Tyne) is found to have increased to. no less than 1,450 feet, and is, moreover, marked by the- appearance of three intercalated beds of limestone quite as important in thickness and quality as the best of our Northum- brian limestones. These three beds form conspicuous features in the country between the Tyne and the Wansbeck, and one of them at least continues to the northernmost extremity of the County. They are well seen about Belsay, and are largely quarried near Corbridge. Accompanying this great thickening of the mass of the strata and the intercalation of three limestones between the Felltop and the Little Limestone there is a very obvious disproportion, between the increase of the shales and that of the sandstones. In the South- West, the total thickness of the sandstones is nearly equal to that of the shales, while here the shales form scarcely one-fourth of the entire mass. Between the lowest of the inter- calated limestones and the Little Limestone is about 1,250 feet in the Matfen district. This is practically made up almost entirely of sandstones and grit, often Very coarse-grained and conglomeritic. At Inghoe, Shafthoe, and Rothley Crags, for Geology of Northumberland. 35 instance, quartz pebbles larger than pigeon's eggs occur, and garnets have been found. These grits — which may appropriately be called the " Inghoe Grits "—'were formerly generally con- sidered as being of Millstone Grit age, and it is to be noted that as they lie above the" Great Limestone " they would be rightly so placed according to the late Prof. J. Phillips's classification, which is, however, in no otherwise applicable to the district. Proceeding North of the Coquet, the " Inghoe Grits " thin considerably, as, indeed, is the pase with most of the groups of beds which are abnormally thick in the centre of the County.* The next limestone in descending order is the " Little Lime- stone;" an extremely constant bed although not always easily seen, being seldom worked for lime. From the Alston district to the Wansbeck it is well-known under the name here given, but further North it receives a variety of names such as the following: Licker Limestone, Chirm Limestone, etc. A well-known seam of coal lying below this limestone has given it more local importance than it would otherwise have gained, and a very few feet below this coal there occurs locally in the South and North Tyne districts another intercalated lime- stone, a thin bed seldom visible, but exposed in the bed of the South Tyne below Allerwash, and in that of the Silly Burn, North- East of Haydon Bridge. A variable thickness of strata, averaging about 50 feet and usually consisting of good building sandstone (the " Black Pasture " stone) and a thick shale below, separates the " Little " from the "Great" Limestone. This latter bed is perhaps the best-known of any of the Series and affords a splendid geological horizon. Notwithstanding faults and occasional eclipses by Drift this limestone can be traced with absolute certainty along the entire line of its outcrop in Northumberland. It is quarried almost everywhere, and very frequently forms a distinct feature in the scenery of the country. Its fossils are better known than those of any other bed in the region, and it may well be looked upon as the type of the Bernician limestones. At Whittington, near Matfen, it is more than forty feet thick, but further North it is thinner, averaging from 25 to 30 feet. It is known by several names along its outcrop, the principal being the "Main" and " Ten- Yard " Limestone. Forming a very regularly-parallel line with, and to the West of, that of the " Great Limestone " is the equally constant " Four-Fathom Limestone," the chief stratum between these being a massive Sandstone very much used for building purposes, and known by various names, the principal being the " Quarry * See G. A. Lebour " On the Little Limestone and its accompanying Coal in South Northumberland." Trans. Min. Inst. 1875. Vol. zxiv., p. 73. 36 Outlines of the Hazle," in the mining districts, and the " Prudhamstone " in Tynedale. This limestone attains a thickness of forty feet at Lippwood, near Hay don Bridge, but further North it varies from 20 to 30 feet only. It was in this limestone that the interesting Foraminifer was first found in 1868, -by Sir Walter C. Trevelyan, at the Elf Hills Quarry, near Scot's Gap, which has since made some stir in the Geological world under- the name of Saccammina Carteri, given to it by Mr. H. B. Brady, F.R.S. This organism occurs in bands in the Limestone, and for some time was thought to be peculiar to it in Northumberland. It has now,. however, been found at several other horizons, chiefly by Mr. W. Topley, F.G.S., in the North of the County, the Rev. W. Howchin, in the Halt- whistle district, and myself. Still, the Limestone can very fairly be called the " Saccammina Limestone," a name which I gave to it in some of the maps of the Geological Survey, as nowhere else has Saccammina been yet found in such quantities or so con- stantly present. In the mining district of Allenheads, so marked was the fossil that that portion of the limestone which contained it was commonly known to the miners as the " spotted post." * Although the name Four-Fathom Limestone is only strictly appropriate in the Alston district, yet it is attached to this lime- stone for a considerable distance to the North, when it changes its name (if change it can be called) to " Eight- Yard Limestone," by which it is very generally known North, of the Coquet. Its chief other name is the " Lowdean " Limestone. The next limestone is almost as easily traceable as the two last, and is marked almost everywhere along its course by, an overlying bed of shale containing nodules of ironstone, which have from time to time been worked, but without much success. Old workings, where the fossiliferous nature of the shale can be seen, are to be found along the crop of the bed between the Haltwhistle Burn and Bardon Mills, at Brinkburn, Lowick, etc. The names of this limestone are somewhat puzzling, as in the South-West district it and the following bed are" both called sometimes the " Three-Yard " and sometimes the " Five-Yard " Limestone. In the Northern district, however, it appears to be generally known as the " Six-Yard " Limestone ; among its other names is The " Acre " Limestone. Another marked bed of shale, frequently fossil-bearing like that last mentioned, caps the succeeding bed of Limestone.- The latter is the last of the calcareous bands which we can with safety (at present) carry from the Alston district entirely across the County. It has been named the Beadnell Limestone by Mr. . * I understand that since .the. above was written this fossil has been detected by Prof. H. A. Nicholson, of St.-Andrew's in some Scottish rocks of Silurian age. Geology of Northumberland. 37 Tate, from the place on the coast where it can be best seen, but besides this and the names " Three " and " Five " Yard Lime- stone which it bears in the Tyne district, it, like the others, is furnished with a variety of appellations of which these, are the principal : the " Eelwell " Limestone, " Main " Limestone, " Sunderland " Limestone, etc. Leaving out the non-continuous beds already spoken oi, we have now enumerated in descending order six distinct calcareous horizons which can be clearly observed from one end of North- umberland to the other. With the exception of the very marked local thickening of the beds in the Matfen district, between the topmost. and the second of these horizons, the thicknesses of the shales and sandstones intervening between them do not vary greatly in this long distance, and the correlations are compara- tively easy. But if the upper members of the Bernician Series can thus be correlated from South to North with safety, this is no longer so as we descend lower down >n the Series. Several elements of difficulty here interfere to hinder the formation of a true comparative scheme applicable to both South and North. In the first place, a large extent of country, involving probably considerable stratigraphical changes, intervenes between' the Penine Escarpment, where alone the beds below the so-called Tynebottom Limestone are exposed on the South, and the southernmost point at which they are visible in Northumberland. Secondly, when we do reach them we find that they comprise a number of limestone beds so much larger, than in the South- Western area, and with such a scarcity of distinctive features, that any attempt to follow Westgarth Forster's nomenclature is as yet hopeless. Moreover, the central district,' as in the case of the Inghoe Grits, shows an immense development of the aggregate thickness of the lower beds as well as an -increased number of limestones. Thirdly, when the Northernmost area is carefully examined, although the thickness of the whole is reduced to something like its original type, and the number of limestones is once more comparable to that at Cross Fell, yet to name these beds in accordance with any system originating from a knowledge of the South-Western region would be fraught with much diffi- culty and almost certain failure in the present state of our knowledge. A list of the chief Coal-seams belonging to this great Limestone Series in the Southern half of the County (a first and probably imperfect attempt) will now be given, and will be followed by a similar one of the better-known Northern district. 12. Felltop, Limestone Coal. Below the Felltop Limestone; some- times called the Newton Underwood Coal, in the Wansbeck and Font district. 38 Outlines of the ii. Belsay and Netherwitton Coals. Below one or other of the intercalated limestones above the Inghoe Grits. Three seams seldom worked. 10. Oakwood Coal. In the Inghoe Grits. Apparently of local occurrence only. Worked at Oakwood, near Acomb, in the Hexham district. 9. Little Limestone Coal. Below the Little Limestone. In one, two, three, or even four seams. Present from the Alston to the Berwick district. This coal is known under a great variety of names, of which the chief are Acomb Seam, Blenkinsopp Coal, Haltwhistle Coal, Clarewood, Inghoe, Boghall, and Cambo Seams. 8. Great Limestone Coal. Just below the Great Limestone. A thin seam seldom worked, but tolerably constant. It was formerly worked at Great Whittington. 7. Shilbottle Seam. Below the Six-Yard Limestone. Present, but very thin and irregular, in the Southern half of the County. Proved at Little Bavington. 6. Cowden Coal. Below the Whin Sill. In the West Bavington district. Worked at Carrycoats. 5. Gunnerton Coal. Position doubtful, but below the last. 4. Wark Coals. Position doubtful, but probably near the last. The Greenlees Coal, worked formerly close to Greenlee Lough, is believed to be on this horizon. 3. Redesdale Coals. Exact position' in the series doubtful, but certainly low down. To this group are referred the seams known as the Stiddle Hill Coal, the Upper Hall Seam, the thin Bellingham Coals .(Carriteth, Brier Edge, etc.), the Elsdon Seams (Andrew's Close, Soppit, etc.), and those worked at Hareshaw Head and Browrilees. The correlation of these seams is a matter of great difficulty, and some years' constant attention to the subject in the field have thrown but little light upon it. a. Plashetts Coals. Below the Dun Limestone and the Piper's Cross Limestone (sometimes called the Papist's Cross Bed). This group consists of three chief workable seams, viz. :— a. — Plashetts Coal. b.—Gneneyes Seam. Separated from the last by the Green- eyes Crag Sandstone. c. — Shilbumhaugh Seam. Separated from the last by a great thickness of rapidly alternating shales and sand- stones, the former largely predominating, and full of fossil Entomostracans. Geology of Northumberland. 39 Above a is a seam know as the " Thirty-inch Coal," which lias been worked in places in a very small way, and between b and c ■comes another thinner seam which has been worked at Starslee. I. Lewis Burn Coals. These are separated by a considerable thickness of rock (chiefly massive sand- stones with interbedded thin ripple-marked flaggy and impure limestones) from the Shilburnhaugh coal horizon. The coals are more splint-like than most of those already named, and where -they are best seen — in the Lewis Burn valley — they are disturbed and dip at very high angles owing to numerous faults. The following is a list, in descending order, of the Bernician. Coal-seams which have been worked in the North of the County, beginning with the Little Limestone Coal : — ia. Little Limestone Coal. Below the Little Limestone. In three or even four seams, known as the Parrot, the Rough, the Licker, and the Chirm Coal. The Rough and Licker seams are those chiefly worked. II. Great Limestone Coal. Below the Great Limestone. Called the Dryburn Coal. Very variable in thickness and seldom worked, except in the Lowick district. 10. Shilbottle Coal. Below the " Six Yard " Limestone. Called also the Acre Coal. It is very variable in quality and thickness and is best at Shilbottle. Tate says that there " it is the best coal in the Mountain Limestone formation." g. Beadnell Coals. Below the Beadnell Limestone. Two seams, of which the lowest attains a thickness of 6 feet. This is known also as the Eelwell Coal; . -. 8. Oxford Limestone Coals. Below the Oxford Limestone^ Four principal seams, viz. : — a. — The Greenses, Allerdean, or • Swinhoe Coal, b. — The Muckle Howgate,. or Fleetham Coal, c. — The Little Howgate Coal, d. — The Upper Scremerston Main Coal. 7. Dunstone Coals. Below the Dun Limestone. Three seams, of which the two lower are the most important and are still worked, viz. : — a. — Raby's Coal. b. — The Fawcett or Caldside Coal. This seam is looked upon in the district as lying usually forty fathoms below the Hobberlaw Limestone. 6. Blackkill Seam. Reckoned as being about ninety fathoms below the, Little Howgate Coal. This seam is also named the "Scremerston Main" and the "Craw." coaL 4© Outlines of the 5. Hardy Coal. Two or three fathoms below the last. Some- times in two seams, when the upper is called the. Hardy, Stony, or Kiln Coal, and the lower the Diamond Coal. 4. Bulman Coal. Five fathoms below the last. Called also th& Cancer or Main Coal. 3. Three-Quarter Seam. About 18 fathoms below the last. 2. Cooper'EyeCoal. Three or four fathoms below the last. Known also as the Stony or Lady Coal. A very variable seam, formerly worked at Eglingham. 1. Wester Coal. From ten to twelve fathoms below the last,, and the lowest worked coal of the series. The table now given is an attempt at a correlation of the- h'orizons of the Bernician Series from South to North, as indicated by the coal seams : SOUTHERN DISTRICT. CENTRAL DISTRICT. NORTHERN DISTRICT. Crow Coal, or Upper Coal Sill. . Felltop Coal. Belsay Coals Netherwitton Coal. Oakwood Coal. ^nd L L m o e w Coal^lf.'.^. 11 ^} Little, Limestone Coal .. {R^ Rgg, *IJd»r Great Limestone Coal . . Dryburn Coal. Shilbottle Coal Shilbottle or Acre CoaL - Beadnell Coals. (Cowden Coal ... Wark Coals ..... Redesdale Coals. Coa Sr(?Y.tT. CTb . yS . c ! r . L !! n f:} piasiietts c ° ais < ? > - Oxford Limestone Coals, . Dunstone Coals. Blackhill Seam Hardy Seam. .Bulman Seam (Three-Quarter Seam. Lowest Seam (?) Lewis Burn Coals (?).. J Cooper Eye Coal. (.Wester Coal. Besides the Limestones and the Coals, to which, by reason of their importance, we have devoted considerable space, there are .still to be noted the much thicker Sandstones and Grits which, with the shales, make up the rest of the great Bernician series. As might be expected from what has been already said, they are by no means constant over great distances,, and in a sketch of this kind a detailed account or list of beds of sandstone would be obviously out of place. There are, however, three great groups of grits which may be traced with ease over a large proportion of the County, and which, as they contribute very strongly to the- '•fleading features of its scenery, must not be passed over. These; are: — $*,The Inghoe Grits. Lying high up in the series, between the- Felltop and the Little Limestone, and attain- ing : their greatest thickness, as has been explained before, in th& Geology of Northumberland. 41 Inghoe district, between the Tyne and Wansbeck. They it is that form the bold coarse-sandstone hills, sloping with the dip towards the former river, on its North bank, between Corbridge and Fourstones, and again between Bardon Mills and Haltwhistle. Occasionally interbedded among the grits are fine-grained, and sometimes flaggy, Sandstones, in places rich with the casts of marine shells. The bands of shale which occur in some number are quite subordinate to the arenaceous beds. To the South of the Tyne the " thick-grit " character of this series merges into that which belongs to it in the Alston district,, where it is chiefly marked by two well-known beds, the Whet- stone Sill, a fine-grained, and " Pattison's Sill," a tough sand- stone. 2. The Simonside Grits. This thick series of grits was first described by Mr. Topley, F.G.S.* They ' form the very conspicuous Simonside Hills, which rise to a height of nearly 1,600 feet on the South side of the Coquet, near Rothbury. This is quite their greatest development, as they decline in thick- ness and feature-making power both to the North and to the South of that point. To them belong the range of crags running from Rothbury to Callalee on the one hand, and those from Simonside,, on the East side of Billsmoor Park, to Hartside Pike near East Woodburn, and the Wanney Crags just South of the Wansbeck Valley Railway. Thence across North Tynedale, and ranging North of and parallel to the line of the Roman Wall, their crag- like character is kept up under very numerous names. But the shales and limestones between the individual grits assume a greater importance to the detriment of the grit-like nature of the group as such. Indeed, names like those which are here adopted to distinguish the grit ranges must only be regarded as convenient for special districts. They do not correspond with definite natural divisions, holding good over considerable distances, and the constant thickening and thinning of the grits themselves,, which may be likened to a kind of Cyclopean false-bedding, prevent the tracing of the component members of each group separately 1. The Harbottle Grits. This group is apparently only clearly defined in the region whence its name has been taken. There (around Harbottle, on the Upper Coquet,)- we have a mass of grits comparable in thickness, lithological characters, and in the constantly varying thickness of the beds of which it is formed, with the Simonside grits. Their upper limit is tolerably well defined by means of the lowest of a set * See Geological Chapter in the " Guide to Rothbury and Upper Coquetdale,'" Alnwick, 1873. 42 Outlines of the of thick blue limestones of the ordinary Bernician type crossing from Redewater into Coquetdale, on the high moors between Grasslees and Horsley or Rochester. The base-line is still better defined in this locality, as the Grits on the South side of the Coquet between Holystone and Linnsheeles immediately overlie thin bedded shales and cement stones of obvious Tuedian aspect. The Harbottle Grits are thick in this, the typical tract, where they form the Beacon and the Drake' Stone Hills, but become thicker still as they spread out to the West and South- West, forming the great sandstone crags which stand out like the tiers of vast amphitheatres at the head of Rede and North Tyne. To this group must be referred the Countess, Ellis, and Christen- bury (?) Crags, and also the Peel, Deadwater, and the greater part of the Carter Fells. This great bottom Bernician group enters the County from Cumberland, near the head of the Irthing, and from Scotland, along the Liddellwater, and thence to the Coquet its presence is made splendidly manifest in some of wildest mountain scenery to be found along the border. Seldom falling below the iooo feet •contour-line, and frequently approaching that of 2000 feet, it rises far above boulder-clay and drift, with a very low and rolling dip which helps to a great degree to multiply the extent of its craggy outcrops. These beds, although the lowest in the Carboniferous Lime- stone series, where, too, this series is of a great and almost abnormal thickness, have sometimes been, like some others already referred to, regarded as Millstone Grit — chiefly, it is presumed, because some beds in it, as, for instance, that to which the great semi-boulder known as the Drake Stone belongs, have been nsed for the manufacture of Millstones ! No better proof could be found of the misleading tendencies of lithological names when applied to stratigraphical groups. To the North of the Coquet the characters of the Harbottle Grits are, to all appearance, gone. Whether the detailed working out of the beds, now proceeding in that part of the County, will •explain this, I know not, but that a very material change does take place is very evident. Either a bodily thinning out occurs here on a very large scale, or the nature of the beds change, as there appears to be no reason to suspect a fault or faults so great as to produce the effects observable. The "almost sudden ■thinning out" theory seems the most probable, as it would account, not only for the state of things in the Northernmost part of the County where no group on such a scale as this one is to be found, but also for a curious and otherwise unexplained series of very high dips which are to be found in the adjoining and over- lying Rothbury Grits. Geology of Northumberland. 43 As will be seen in the chapter devoted to the lowest Carboni- ferous or Tuedian Beds, the Harbottle Grits may come to be claimed — as indeed they have been already— as the upper mem- bers of that Series. CHAPTER IX, THE TUEDIAN BEDS. Under this name are grouped those lowest Carboniferous beds which in Scotland generally go by the name of "Calciferous Sandstones" — a name given them by Maclaren in 1839. Pro- fessor A. Geikie, F.R.S., has shown that the lower portions of these rocks merge insensibly into the upper part of the Old Red Sandstone Series. In Northumberland their upper limit is equally indefinite, the higher beds of ftiev division dove-tailing into the lower beds of that next above (fhefBernician). No hard and fast line can therefore be drawn either "at the base or at the top of the Tuedian Series here, but notwithstanding this the beds of that division have most of them a distinct character of their own. The Sandstones of which they consist to a considerable exterlt are not unlike those of the Bernician except towards the base of the series where they generally contain rolled fragments of Cheviot porphyrites, these fragments increasing in size as we get closer to the parent mass, and being accompanied by a deepening brownish-red tinge. This is well seen at Biddlestone where, in the Burn running behind the Hall, an excellent section showing the change from the mere coarse yellow sandstone to a dark-coloured conglomerate is very marked. Still better can this be studied in the fine section at Roddam Dene, where the Porphyritic conglomerates are splendidly exposed. Smaller and less clear sections showing this bottom character of the series are to be found at other localities on the- flanks of the Cheviots, and in all cases these coarse reddish rocks have been looked upon as Upper Old Red Conglomerate. It seems, however, much more philosophical to hesitate before drawing a line between these red rocks and a series which is — as the recognized Tuedians undoubtedly are — in every respect simply an undisturbed continu- ation of them. The entire mass is therefore here called Tuedian. Adopting this course then, the lower limit of the Tuedians in this county is defined by the outline of the Cheviot rocks which had long been erupted and stood as an island in the lowest Carboni- ferous or Upper Old Red Sandstone Sea. The upper limit is not 44 Outlines of the so easily traced — indeed it cannot in many cases be traced at alL Convenience and expediency have, however, determined the choice of certain beds at various points as denning the top of the series, but it must be borne in mind that the line thus obtained is purely arbitrary, and that a true boundary separating Tuedian from Bernician rocks would not keep to any one horizon, but would be represented by a zig-zag, the accurate delineation of which would demand a perfectly accurate knowledge of the minor details of the beds such as there are no means of obtaining at present. In practice the Tuedian rocks are said to begin (proceeding downwards) where the limestones of the Bernician Series lose their usual Carboniferous Limestone type, where they become -cream-coloured, hard, unfossiliferous, and magnesian, and where they assume the character of cement stones. To the North of Berwick, the lowest accepted Bernician lime- stone is the Dun limestone, well-known throughout the Northern part of Northumberland, but only with great reserve to be correlated with a bed of the same name in the Upper North Tyne district. This is the limestone which crops out for some miles along the coast at Lamberton. Though thin, it is extremely rich in the ordinary fossils of the Limestone Series. , This has been taken by the Scotch Survey, North 1 of Berwick, and by Mr. E. F. Boyd, South of the Tweed, as the line separating Bernician from Tuedian, and for that region it may well be adopted here.* But in the upper .Coquet district, where the Tuedians are extremely well developed, no such limestone can be traced, and the Har- bottle Grits, already described, are so thoroughly Bernician in facies, and so well divided stratigraphically from the Tuedians, that there the base of this great sandstone series forms quite the most convenient boundary line. Now, there is little doubt that the horizon of the Lamberton or Dun Limestone is above the Harbottle Grits, so that the merely expedient and artificial char- acter of the boundaries thus arrived at is shown, at once. The. truth is, that no line should be drawn at all, except as the merest matter of convenience. An awkward result of the above-described state of things is this; The Harbottle Grits and the great grit series to the West of Chillingham are perhaps the same ; at any rate, they are not far separated in age. In both these deposits the remains- have been found of a shell, which is characteristic of the Yellow Sandstone. Series (= Tuedian) of Ireland, the Anodonta, Jukesii* Hitherto, this shell has not been found elsewhere in England.} * The Rev. W. Howchin, F.G.S., of Haltwhistle, has kindly searched some wash- ings of this interesting' bed for me, and has framed a valuable list of the microzoa contained in them. (See list of fossils in the last chapter.) t See Lebour's " Catalogue of the Hutton Collection," p. 123. Also R. Howse„ Nat. Hist. Trans. Nortuumbd. & Durham, Vol. vii., Part i„ p. 173. Geology of Northumberland. 45 Had the line we have taken been anything but confessedly an artificial one we should have been compelled to explain the occurrence of this eminently Lowest Carboniferous fossil, both above and below that line ; but as it is, there need be no real difficulty about the matter, A more or less broad margin must be 'allowed on either side of the line — true passage beds in fact — which may be said to belong, and do actually belong, to both Bernician and Tuedian. The discovery of Anodonta Jukesii in the lowest Bernician does not affect its Tuedian — in this case, Upper Tuedian— character. The cement stones, as all the Tuedian limestones are more or less, are very frequent in the series, but they do not appear to be at all continuous, although tolerably thick in places. They can be well studied in Upper Coquetdale, where (as at Alwinton, Biddlestone, etc.), they have at times been burned for agricultural purposes, although they are not very well suited for the purpose. No fossils have, to my knowledge, been found in these calcareous beds. At Hetchester, near Hepple, on the Coquet, several beds of limestone are worked, the exact position of which is doubtful. There their character is entirely Tuedian, and they are peculiar in lithological structure. They are all minutely oolitic, that is to say, composed of small round or oval many-coated concretions of a more or less siliceous nature, and. they are exceedingly hard. Besides the limestones, the shales and sandy clays of the Tuedians are decidedly characteristic. The former are very •commonly purple, and the latter greenish, thick, occasionally . marly, and full of hard amorphous siliceous concretions ; they are well-shown about Holystone and Sharperton. Some small ill-shapen Brachiopods, belonging apparently to f he genus A thyris, and some large but very imperfect specimens of Nautilus, have been found in the Shales at the Barrow Scroggs, in the Upper Coquet. So far as I am aware, these are the only marine fossils yet found in the Tuedians of Northumberland. The Sandstones abound in Sigillarian and Lepidodendroid remains, with a few Calamites.. The Genus Ulodendron appears to be especially plentiful in these beds. The name Tuedian was' proposed by the late Mr. George Tate, in 1855, and after a period of neglect it bids fair now to hecome the acknowledged title of the series.* * See Lebour " On the Terms Bernican and Tuedian." Geol. Mag., Decade ii. r Vol. iv. (1877.) 46 Outlines of the CHAPTER X. THE SILURIAN ROCKS. In the extreme West and North-West of the County rocks of Silurian age are known, but they afford no positive evidence of their exact age. They consist near the head of the Redewater of high-dipping and occasionally contorted greyish, greenish, and purple shales, or clay-slate, through which run narrow dykes df compact Dyorite. No fossils ihave up to the present time been found in these beds, which occur merely as an inlier of very limited extent upon which the lower beds' of the Carboniferous Series rest. They are well seen in the road-cuttings along the Chevy Chase Road to Scotland, at and around the inn at Whitelee, and in the beds and banks of the Rede and the Whitelee Burn, but their area is very small. It may be noted that this mode of occurrence of the older rocks beneath the Carboniferous Series is, in most respects, similar to that of the Silurian strata in Tees- dale, except that, in Redewater, there is no evidence of, and no necessity for, the presence of any dislocation to account for them. The age of this small uncovered patch of Silurian rocks is, of course, doubtful, but they may be referred, without much hesita- tion, to the Riccarton Series. The, only other Northumbrian locality known to us where rocks of this character occur is among the Cheviots in the Upper Coquet. Here, between Philip and Makendon,* the Porphyrites which form the main mass of the range are seen, in a beautifully clear section, abutting against grits of Silurian age or " greywacke." The latter are bent up on end by the intrusion of the former, thus giving a limit of age to that event, as stated elsewhere (p. 3). ' Geology of Northumberland. 47- CHAPTER XI. IGNEOUS ROCKS \ DYKES. The igneous rocks of Northumberland are of many kinds, but they can conveniently be grouped under three heads, viz. : — 1. Basaltic Dykes, probably of Tertiary age. 2. Sheets and bosses, of post-Carboniferous, but probably Pre-Triassic age. 3. Porphyrites, etc., of post-Silurian, but pre-Carboniferous. age. 1. Dykes. — These, with one or two rare exceptions, are remarkably uniform in lithological composition. , They are, as a rule, clqse-grained Basalts, deep blue when freshly-broken, with strong conchoidal fracture, weathering to brown and red, and very commonly into spheroidal balls. It would not answer any useful purpose to enumerate all the dykes known, but a few of the more remarkable must be mentioned. The bearings of the dykes are many, but a very large majority run in two main direc- tions, one set being East and West or South-East and North- West ; and the other, roughly, North-East and South-West. The former appear to belong to the same category as the numerous Tertiary Dykes which follow parallel courses across the South of Scotland, one of them, indeed, the Acklington dyke, being doubt- less merely the South-Easterly continuation of one of these Scottish dykes. The reasons for considering the latter as of Tertiary age have been worked out with great success by Prof. Geikie, Mr. Jack, and others, and there seems to be none to urge against their application to some (and, by analogy, to all) of those South of the Tweed. The supposed Triassic age of some of : the Northumbrian Dykes requires proof. The dykes vary greatly in width, that at Holy Island being the thickest on the whole, although others sometimes attain, locally, an equal breadth. Most of the dykes are single so far as they are known to me, but a few are proved to split up into branches, whilst others are suspected of doing so. In a few cases the dykes are seen to overflow laterally. The Acklington dyke, for instance, as it approaches the Cheviot Porphyritic mass, through which it cuts, spreads irregularly over the beds of Tuedian age in which it is encased. This is very 48 Outlines of the beautifully seen along its course from a little to the South- West -of Biddlestone to the banks of the Alwin, at Clennell. At Shil- bottle, two " beds " or " sheets " of whin are known which may be lateral dyke-overflows of a similar character, but which have also been referred to the Whin Sill. Mr. I. L. Bell, M.P., F.R.S., has published a very interesting paper on the composition of the basalt of the overflowing limbs of other dykes near their junction with the surrounding sedimentary rocks.* ' Some of these dykes, which are well-known through having been met with in underground workings, do not reach the surface at all, and many which are seen " to the day " do not continue at so high a level for any distance. In some rare cases the actual natural top or vertical dying out of a dyke can be seen, as on the Coast a little to the South of Seaton Sluice. Here, near a spring on the beach, a dyke, at least 12 feet in width where it rises at the foot of the cliff,' is finely shown ending off in two tongues of basalt, the longest of which, after curving amongst disturbed and contorted shale, dies out about 11 feet from the ground beneath a bed of Sandstone, which it had not the force to break through. The fault along which this dyke was injected" is well seen con- tinuing its. upward course. A more instructive section it would be difficult to find. The dyke which crosses, the Wansbeck a few yards below the Viaduct of the North Eastern Railway is much more largely crystalline and blacker in colour than is usual. The Acklington Dyke seems to be usually more or less vesicular and amygda- loidal, a character which does not appear to belong in any marked degree to other Northumbrian dykes. The Tynemouth Dyke, where it is seen by the side of the pier in the Priory cliff, has always been described as consisting of greenstone, and certainly its appearance at that point is different from that of the ordinary dykes. It was formerly only known here, where it is seen to cut through yellow sandstone ; its relation to the Magnesian Lime- stone being unknown. Recently, Mr. FavelL F.G.S., has detected the prolongation of this' dyke to the West near Biddy Mill, and the specimens which I have seen from that locality do not differ from some taken from the common basaltic dykes. Winch remarks that this whin is very like that of Coley-Hill. Of the other dykes the following are some of the more important : — A. — East and West Series. The Hebburn Dyke, emerging from beneath the Magnesian Limestone near Cleadon, runs by Hedworth and Hebburn, ■crosses the Tyne and enters Northumberland at Walker, thence * Proc. Roy. Soc. 1875, Vol. xxiii., p. 543. Geology of Northumberland. 49 by Byker through Newcastle, along the Southern margin' of the Town Moor as far as Slatyford, where it meets the Ninety- Fathom Dyke. For a space it no longer reaches the surface, but re-appears in it original direction as the well-known Coley-Hill Dyke, between Whorlton and Dewley, near to which place it is finally lost sight of. This dyke is confined to the Coal-Measures, and the fact that it does not penetrate the Magnesian Limestone at Cleadon has been made use of as an argument to establish its pre-Permian age. This evidence is, however, purely negative, and standing alone, as it does, cannot be considered of much weight. 1 The Cramlington, Bedlingtcm, and Lower Wansbeck Dykes com- prise some half-dozen parallel lines of intrusion, which are marked by branches of an unusual character. They will be found described in detail in the Survey Memoir on sheets 105 North- West and North-East of the one-inch geological maps. The Acklington Dyke, which has already been mentioned, stretches across the entire width of the County from the Coast at Bondicar, near Acklington, cutting through Coal-Measures, Millstone Grit, the whole of the Bernicians, the Tuedians, and Cheviot porphyries. As stated before, it runs on for many miles across the South of Scotland. It is well seen at numberless places along its course, notably at Debdon, Cartington Castle, Clennell (where it overflows laterally), and the road along the Coquet near Shillmoor. At Acklington it is 30 feet wide. The Trobe's Dene Dyke appears only underground, in the eastern part of the Shilbbttle Colliery, running nearly from East to West.* It is from this dyke that the lateral overflows of basalt mentioned above in connexion with this locality are supposed to proceed. The Beadnell Dyke, well seen on the Coast at the place of that name, is " traceable as far as Newnham Station " (Tate). The Holy Island or Lindisfarne Dyke, the last of the more important dykes belonging to the East and West series, is thus described by Mr. Tate : — " It is one of the largest in the County ( and indeed has been erroneously described as part of the Whin Sill, to which it has some resemblance, as it rises in Lindisfarne or Holy Island in high craggy hills of columnar basalt. It crosses the Southern part of the Island nearly from West to East, and is seen two miles seaward forming the Plough and Goldstone rocks, on which the " Pegasus " was wrecked. The Castle crowns a high craggy basaltic hill, and on the West side of the Island the dyke is exposed in a high cliff, and is there izo feet wide, with a slope 85° Southward ; large blocks of limestone, highly metamor- * G. Tate, F.G.S., Proc. Berwickshire Nat. Club. (1863), p. hi. 50 Outlines of the phosed, are enveloped in the basalt; and the strata, broken; through, have been relatively altered in position ; those on the South side having been considerably upcast. A calcareous shale, very fossiliferous, and a limestone beneath it abut against the dyke and are metamorphosed ; and near to the Castle a vein of basalt penetrates the shale. This dyke is seen near Fenham on the mainland, and further Westward near Kyloe Church, where its width is from 20 to 60 feet, for it widens as it descends; in one part it is covered by shattered beds of shale. It cuts through the Lowick Coal-beds, and is traceable further Westward to Leitham, the whole ascertained course being about 14 miles."* Many small dykes known at various places in the West and centre of the County, in the Bernician area (as at Hareshaw, Wark's Burn, etc.), belong to the same series as those above- named (by their direction), but, as will be presently. seen, the chief dykes of this region belong to the second category, viz. : — B. — North-East and South- West Series. The Brunton Dyke, known in West Allendale, near Whitfield, crosses the South Tyne first to the West of Haydon Bridge, then between that little town and Wharnley, and lastly to the East of the latter place ; it crosses the North Tyne near Wall, is well exposed by St. Oswald's Chapel, near Brunton, and is last seen in the Bingfield Burn. on the East side of the Watling Street. Two small dykes run close to and parallel to this one near its easternmost extremity. Of these, one is well seen in the Bingfield Burn, and the other in the bed of the Pont, where that little stream crosses the Watling Street. The Bavington Dyke begins almost due North of the spot where the last dyke ends, and is quite parallel to it in direction. It is of great but irregular thickness where it is first seen, just South of the Bavington Hall grounds, so much so that it might be taken, at first sight, for the Southern continuation of the' Eastern branch of the Whin Sill, but it very gradually thins away in its North-Easterly course to a yard or less. It is well shown at Bolam in the Park, and is visible in the bed of the Font below the Coal-House Quarries. - The Lewis Burn or Trough-End Dyke is first seen in the County in Short Cleugh, a little valley formed by a tributary of the Lewis Burn ; thence good exposures are frequent, as in the railway cutting East of the Belling, crossing the Tarret Burn at High Green, in the field just North of the Troughend Hall, in the ' Elsdon Burn between Elsdon and High Carrick, on the road from Elsdon to Billsmoor, and lastly (and perhaps best of all), in a * Loc. cit., p. 21P. Geology of Northumberland. 5 1 deep Cleugh in the high hills between Billsmoor Park and Darden Lough, whence it has been traced to the South of Tosson, as I am informed, by Mr. Topley. This dyke is, sometimes, very inappropriately called The Falstone Dyke. The Black Bum Dykes are two or three in number, and occur exactly parallel to and within a short distance of the last dyke to the North. They are well seen in the Black Burn, which runs into Tarret Burn, but have not yet been traced any distance. The Plashetts Dyke (already referred to at p. 6) is of uncertain direction, although in a general way it may claim to find a place in this series. It forms the Eastern boundary of the Plashetts Coal-workings and is not seen at the surface. The Boubner Dyke t which, according to Tate, is only seen on the coast, is 100 feet wide. The Hampeth Dyke, 150 feet wide, is seen in Hampeth Burn, South-West of Shilbottle. The Howick Dyke, belonging to this series, is interesting because of its nearness to the Whin Sill, with which, however, it cannot be actually connected. It is only seen on the coast. The Cornhill Dyke, cutting for seven miles through Tuedian and Bernician beds, from half-a-mile below Coldstream to Milkington, Heaton Mill, and Mattalees, seems to belong to these dykes. Many of the dykes above described have altered and baked the deposits through which they cut, but their effects are by no means constant, coal being sometimes completely coked, and sometimes but very slightly, if at all, affected by contact with them. Most of the dykes in the Coal-field are remarkable for the coking which they have produced, as, for instance, the; Hebburn dyke. CHAPTER XII. Igneous Rocks Continued: The Great Whin Sill. This is the name given to a sheet of Dolerite, the outcrop of which stretches across Northumberland from Greenhead to a few miles South of Berwick, and which probably underlies almost the whole of the Southern and Eastern portions of the County. Of undoubted igneous origin, this flow of Basalt has yet given rise to- much contention among Geologists, some arguing that it was a regularly interbedded trap, the mineralogical character of which alone distinguished it from the beds above and below, and others, with — as it has since been proved — more reason, that it was a 5? Outlines of the purely intrusive mass injected just as the ordinary dykes are, long after the deposition of the rocks amongst which it lies. The evidence relied on by the former party was chiefly that in the mining district of Alston Moor, and the South Tyne, the Whin Sill did appear to he regularly at one horizon. That on the other side, which appears to Be perfectly unassailable, being found in the altered, or metamorphosed, character of the rocks above the Whin Sill, especially when they consist of shales, and in the fact that the Whin does not lie at one uniform level amongst the sedimentary strata, but frequently comes up in bosses, cutting through the rocks, and shifting its relative position amongst them to the extent of 1,000 feet or more in short distances.* The importance attached to a settlement of this question of ■ the intrusion of the Whin Sill is due, to some extent, to the fact that the late Professor Phillips relied upon that basaltic sheet as a boundary between his two great divisions of the Carboniferous Limestone Series, the Yoredale Rocks and the Scaur Limestones. As it is now shown that it shifts its position, being sometimes found below, but more often above the supposed base-line of the Yoredale Beds, its value as a line of boundary is entirely lost.-}- The Whin Sill is wholly comprised within the Bernician Series in Northumberland, and chiefly within its upper portion. On entering the County the Whin is, for a space, found lying above the "Great Limestone," some 700 or 800 feet above its Alston horizon, but returns to its more usual position before long, about which, with fluctuations above and below, within about 300 feet, it keeps for many miles, crossing the North Tyne, near to which river it assumes the North-Easterly trend followed by all the beds of the district. At Low Teppermoor it is seen at about its lowest position in this portion of its course ; and here also a surface break (of which there are several along the crop of the sheet) is very well shown. Thence it continues to the North- East, pretty much along the same horizon, till it reaches Swin- burne Mill, where another break occurs, accbmpanied by a rise of a few fathoms to the next higher bed of Limestone. From this point the Whin Sill runs almost due North, in a fine line of semi-columnar crags, as far as Knowes Gate, where it crosses the Wansbeck Valley Railway. In this distance it is twice inter- rupted by surface breaks unattended with change of horizon — at Sweethope and the Berry Hills. A little to the North of the line this long basaltic range terminates abruptly, re-appearing at * See Topley and Lebour " On the Whin Sill in Northumberland." Brit. Assoc. Report for 1873, Part 2, p. 92. t Lebour " On the Limits of the Yoredale Series in the North of England." Geological Magazine, Decade ii., Vol. ii. (1875), p. 539 Geology of Northumberland. 53 intervals through a drift-covered country., Parallel, to this great ridge, however, and not quite a mile to the East of it (three beds of limestone with their associated sandstones and shales inter- vening), is another equally thick- (and in places even thicker) but much more regular sheet of Dolerite, which may be looked upon as a branch of the Whin Sill, and which runs from Homilton, near Bavington, to Elf-Hills, to the North-East of Kirk-Whelpington. This Eastern sheet is much more subject to breaks than the main or Westerly one, and towards its northern extremity comes to the surface usually not as a continuous bed, but in bosses or isolated masses of greater or lesser size. About half-a-mile to the North of the village of Chollerton there is a patch of basalt quarried in a small plantation by the road-side which is probably a separate boss belonging to the branch of the Whin Sill just mentioned. This is rendered more probable by the fact that a thin bed of basalt (rather light- coloured and very fine-grained) is seen in the bed of the North Tyne a little below Haughton Castle. This thin bed may be the Southernmost exposure of the Eastern Whin Sill. At Elf-Hills Quarry, where the Four-fathom Limestone was until lately wrought, the Whin overlies and breaks through the limestone, but a more interesting case of intrusion was observed here by Sir- Walter C. Trevelyan a few years back, when a thin layer of fine-grained Whin underlying the limestone was seen sending up strings of trap through the overlying limestone beds. At the extremity of these shoots of Whinstone a singular black earthy substance was noticed, the like of which has since been detected by Mr. David Burns, F.G.S., of H.M. Geological Survey, elsewhere at the point of junction between Whin and Limestone.* On partially analysing a portion of this stuff, Mr. J. T. Dunn, B.Sc, of the Newcastle College of Physical Science, ascertained that it contained as much as 17 percent, of combustible and volatile matter — probably free Carbon. This, taken in conjunction with the fact that the Whin' Sill in its irruption undoubtedly absorbed , portions of the beds through which it poured, tends to confirm certain theories advocated by Mr. Burns in the paper referred to. At Elf-Hills too, pieces of shale some feet in length may be seen caught up and enclosed in the basalt. To the North of Elf-Hills there is a broad flat tract of drift- covered land, beyond which the Whin is again seen (at Harting- ton and Gallow Hill) lying in the same position, i.e., between the Great and Four-Fathom Limestones. Again there is a broad drift-covered valley beyond which the Whin is seen at Dyke- Head. It here seems to come up as a great boss, and lies lower * D. Burns " On the Intrusion of the Whin Sill." Trans. N. Engl. Jnst. Min. and Mechan. Engineers, Vol. xxvii. (1878). 54 Outlines of the in the series* A bore-hole put down on the South side of Greenleighton Farm found the Whin just below the Six-yard .Limestone.* In Fallowlees Burn the Whip lies about ioo feet below the - position last mentioned. From this place it can be traced for about a mile to the North, apparently keeping at the same horizon. At Ward's Hill, near Forest Burn, the Whin lies above the Great Limestone. It is not seen again until about four or five miles South of Alnwick. Thence it can be traced Northwards, past Rugley, nearly to Alnwick, lying about ioo feet, or rather more, above the Hobberlaw Limestone, which is the lowest good and thick limestone in the district. Here, too, the Whin has its lowest known position, as it lies nearly i,ooofeet below the Great Limestone. The beds immediately above the Whin are seen in a stream South-east of St. Margaret's Farm, where they are much altered.-) From this point the course of the Whin Sill has been well described by the late Messrs. W. Hutton and G. Tate, and by Mr. E. F. Boyd. I From Ratcheugh Northwards to Dunstanburgh the Whin lies in beds and bosses at various horizons. • At the former place it is below the Eight-yard Limestone, and the Whin occurs in three separate sheets or flows, separated from each other by altered shale and limestone. At Peppermoor, according to Mr. Tate, there are indications of two intrusions. At Dunstanburgh the basalt forms the fine sea-cliff surmounted by the ruined Castle and overlies the Great Limestone. Thence by Spittleford and Embleton, at or about the same horizon, to St. Mary's Haven and Old Newton. Between Newton North Farm, on the South side of Beadnell Bay and the Farne Islands, the Whin Sill is nowhere to be seen. The Islands are, however, entirely formed of it, except where some considerable patches of altered shales, lime- stones, and sandstone occur, apparently enveloped in the trap. Similar cases of enclosed sedimentary rocks are well seen on the coast just North of Bamburgh Castle, which, like Dunstanburgh, stands on a cliff of Whin 'Silt columns. § In this portion of the * This is the Three-yard Limestone of Teesdale. + Most of the above description is taken from Topley and Lebour's paper " On the intrusive character of the Whin Sill in Northumberland," read before the Geological Society of London on December the 6th, 1876, and published in the Quarterly Journal of the Society, Vol. xxxiii. (1877), p. 406. t W. Hutton in Trans. Nat. Hist. Soo. Northumberland, etc., Vol. ii., p. 187 (183a). G. Tate in Proc. Berwickshire Nat. Club. Vol. vi., p. 197. E. F. Boyd in Trans. N. Engl. Inst. Min. & Mechan. Eng. Vol. ix., p. 185 (1861). i See Sir W. C. Trevelyan, Mem. of the Wernerian Society, VoL iv. (1823), p. 253, and Lebour and Fryar " On the Harkess Rocks near Bamburgh." Trans. N. Engl. Inst. Min. and Mechan. Engineers, Vol. xxvi. (1877). Geology of Northumberland. 55 mainland the Whin covers a large extent of country and is very well seen indeed both along the sea-coast and inland towards Belford, the celebrated Spindlestone Crags belonging to it. Thence, with important breaks partly due to large faults, the basaltic range runs to the Kyloe Crags by Middleton and Knucton. Throughout this long serpentine course the Great Whin Sill, although it shifts its horizon continually, yet follows in a general way the strike of the sedimentary beds, so that, before, the Geology of the country was worked out in any detail, there certainly was a primd facie likelihood of its being a truly inter- bedded sheet. Its thickness varies very greatly, being scarcely 20 feet in places and 150 feet in others., On an average it is from about 80 to 100 feet thick. That the Whin Sill has been injected between the strata after their deposition and consolidation is now sufficiently •evident. " The exact geological date at which the intrusion took plaqe cannot be determined. Northumberland offers no conclusive evidence on the subject ; but, so far as the evidence in this and other districts goes, it seems probable that the intrusion took place at the close of the Carboniferious period."* Speaking lithologically, the Whin Sill is thus described by Mr. S. Allport : — " A specimen of it from Ward's Hill, near Rothbury, is a well-crystallized greyish black basalt containing the usual constituents ; the plagioclase is distinctly striated ; the augite occurs here and there in twin crystals ; and there are a few serpen- tinous pseudomorphs of olivine. Grains of magnetite are thickly scattered through it. A dolerite from Elf Hills, in Northumber- land, is not so well crystallised as the preceding, and is more altered ; the augite is partially converted into a grey substance ; there is some disseminated chlorite ; and an altered glass fills ■the spaces between the, constituents.} CHAPTER XIII. Igneous Rocks continued: The Cheviots. The Cheviots proper are as well-defined geologically as they are topographically. No contrast can well be greater than that presented by the high green rounded contours of this " massif," and the rugged craggy heather-clad outlines of the Carboniferous * Topley and Lebour, loc. cit., p. 431. t Quarterly Journal of the Geol. Society, Vol. xxx. (1874), p. 55?. 56 Outlines of the rocks which skirt along their base. Nowhere can this be better seen than from some of the crags of the Harbottle Grits in Upper Coquetdale. Strikingly homogeneous are the features of the Cheviots; the deep valleys of the range, its steep slopes, its hag-Covered sub-conical tops — all are alike from Wooler to * Clennell. To the Geologist's eye, the igneous origin of these hills is evident at a distance, and igneous the entire mass undoubtedly is, but very numerous are the varieties of igneous rocks of which that mass is composed. The area covered by these rocks in this County is about 200 square miles, and the most generalized hst of the rocks found in large masses within this region gives the following varieties : — 1. Granite, only occasionally present, but well-shown in places* as in the hills below " Cheviot," about the head of the Breamish. 2. Syenite, abundant, as at Yevering, " Cheviot," Blindburn, etc. This syenite passes into the granite mentioned above. 3. Porphyrite, comprises by far the most abundant varieties of the Cheviot rocks. Red Porphyrite of a fine deep salmon-red colour is the commonest of all. It is well shown at Biddlestone, for instance, a little to the East of the Hall, where it-is quarried and where the joint-faces are marked with very beautiful dendrites. This red rock passes insensibly into other varieties of the same group of greyish and brownish colours, and these by degrees occasionally lose their original character and become amygda- loidal, the cavities being filled with chalcedony. Fine agates can sometimes be found in sit4 in rocks of this description close to the Ridlees Farm-house in Upper Coquetdale, and good rounded specimens lie among the gravels of Upper Redewater, about Rams- hope, and of the Coquet above Rothbury. 4. Doleritic Rocks of dark colour are only less frequent than the Porphyrites, and are very distinguishable from them when in their typical state, but in many cases it is impossible to draw any line between the two groups of rocks, so gradual appears to be the change from one -to the other. At times, again, these blackish rocks appear sharply defined, as if by intrusion, from the others. In the solitary case (that of the Acklington dyke) in which a whin dyke is, seen cutting through the Cheviot rocks, the nature of the stone is very distinct from that of these Dolerites, although probably they would both be of much the same composition. ' The above are the three chief constituent groups of the Cheviot rocks, but it may be said that from a petrographical point of view the Cheviots are virgin ground yet to be broken. Geologically speaking, much interest attaches to the arrangement of these rocks apart from their composition, and to their age. Geology of Northumberland. 57 Respecting the former point a singular fact is noticeable in many parts of the Cheviots, namely, the marked bedded appearance of some of these igneous ropks. At certain places this appearance of bedding and regular dip is so distinct as to lead one to doubt Whether the rocks be not highly metamorphic and not truly igneous. Apparent dips of this kind can some- times be traced consistently for miles, but at the same time it must be admitted that more usually the self-same rocks are wholly devoid of bedding-like planes, and of anything approach- ing to uniform dip. Almost as much, however, remains to be known respecting the structure, as .regarding the lithological constitution of the Cheviots. • The pseudo-dip and bedding can be seen to perfection on the banks of the Ridlees Burn, where a most interesting section, to be presently described, is to be seen. The age of the Cheviot rocks is probably not the same for the various members of the group. It seems highly probable, for instance, that some of the Doleritic masses are of later age than the Porphyrites, and I would here throw out the suggestion that the detached minor bosses of trap seen piercing through the lowest Carboniferous rocks near the summit of the Carter Fell road are to be assigned to this era in the history of these eruptive rocks. How far the Syenites, with their occasional Granite,' may be separated in age from the Porphyrites I am not in a position to say, but if I am right in the suggestion just thrown out, there would be at least three periods of intrusion represented in the Cheviot mass. An early one (that of the Porphyrites), posterior to the Makendon Silurian rocks, but prior to the Basement beds of the Tuedians; a second one (that of the old Dolerites), in Carboni- ferous times probably; and a third (e.g. the Ackhngton dyke), which was contemporaneous with that of the East and West Whin dykes. These conclusions are based on the following facts : — 1. The Silurian beds at Makendon are, wherever they are seen in contact with the Cheviot rocks, tilted up by the latter. 2. The lowest Carboniferous rocks are, where no faults are present, as at Cottonshope Head and the Ridlees, seen to rest on the Cheviot rocks and are perfectly undisturbed by them. 3. Isolated patches of Lower Carboniferous Sandstqne and of Basement beds are found lying undisturbed on the flanks of the Cheviot, as by the " Clennell Street " above Alwynton, and on Whitelaw, East of Yevering. .4. The Basement beds, like the higher Tuedian beds, are to a certain extent made up of pebbles of Cheviot Porphyrite. 5. Some of the older Dolerites appear to pierce through the porphyrites, although they do not always have that appearance. 5 8 Outlines of the 6. These Dolerites are sometimes, as up Puncherton Burn (running into the Alwyn), seen to pass into a brecciated con- glomerate in which blocks of rock, apparently of Lower Carboni- ferous origin, besides others of earlier age and mixed with frag- ments of Porphyrite, are embedded in a matrix of Dolerite. 7. The bosses of trap seen below Whitelee, by the Carter Fell road, are quite unlike either the dykes and bosses' which are common in the rest of the County, while they are very similar to •the Cheviot Dolerites in the neighbourhood of which they are found. In " Good Words " for 1876, there is a series of articles by Dr. James Geikie, F.R.S., on the Cheviot Hills. The chief Geological conclusions arrived at are thus abstracted : — * " Describes the scenery and extent of the region. The Scottish side is the most abrupt. The age of the igneous rocks, forming the greater part of the range, is intermediate between that of the greywacke beds and of the red and white sandstone (Upper Old Red Conglomerate or lowest Carboniferous), lying unconformably upon them. These igneous rocks consist chiefly of pprphyrites. At Hindhope the oldest of them (the Ash beds) are to be seen. The early volcanic outbursts were submarine ; but those at the close of the period of activity were subaerial. In early Carboniferous times there followed another volcanic period, to which the plugged-up vents of Ruben Law, Black Law, etc., belong. Describes the glacial deposits fully. The Cheviots were covered by the ice-sheet when at its thickest, but they divided the flow between Scotland and England." CHAPTER XIV. Materials for a Palaeontology of Northumberland. For the Permian Fossils the student is referred to Mr. R. Howse's publications in the Transactions of the Tyneside Naturalists' Field Club,t and to Prof. King's Monograph in the volumes of the Palseontographical Society. ' Practically it is now all but impossible to obtain any, except those of the Marl-Slate, at Cullercoats, during the very lowest tides. For the Coal Measure Fossils he is referred to a " Synopsis of Organic remains found in the Northumberland Coal Measures," also by Mr. Howse, published at p. 59 of the " Industrial Resources * See " Geological Record " for 1876, (1878), p. 12. t 1848 and 1852. Also separately printed. Geology of Northumberland. 59 of the Tyne, Wear, and Tees" (second edition, 1864), and for the plants to the " Catalogue of the Hutton Collection of Fossil Plants" drawn up by myself, and published by the Mining Institute in January, 1878. The Gannister Beds were thought to be unfossililerous in Northumberland and Durham until the beginning of the present year, when I had the good fortune to discover some inthe rocks of that age near Whittonstall, to the South of Stocksfield Station. The list is at present a small one, viz. : — Avicuhpectm papyraceus. A v., sp. •Orthoceras, sp. Encrinite Stems. Mr. G. C. Greenwell, F.G.S., informs me, however, that many years ago he obtained some specimens of Goniatites and a Microconchus from beds belonging to this series near Prudhoe. The most interesting fossil-bearing series in the County is, however, without exception, the Bernician, where every limestone, many of the shales, and some of the sandstones, yield their quota of fossils. A full list of all the species that have been found would be out of place here, even were it not ultra vires, but the following detached lists will, I trust, give a sufficient idea of the richness of this fauna. In the quoted lists the nomenclature of each author has been retained. First will be given a list of the - fossils known to occur in the highest or Felltop Limestone : — Felltop Limestone, at Harlow Hill. Lithostrotion junceum, Flem. L. irregulare, Phill. L. Portlocki, Bronn (very pjentiful). Cyathophyttum, sp. Griffithides, sp. Poteriocrinus, 2 sp. (?). Orthisina (StreptorhyhcusJ crenistria, Phill. Productus giganteus, Mart. Pr. latissimus, Sow. Pr. semireticulatus, Mart. Pr. costatus, Sow. Pr. punctatus, Mart. Pr. longispinus, Sow. Pinna flabelliformis, Mart. Chomatodus ductus, Ag. Petalodus acuminatus, Ag. 60 Outlines of the The list which follows is specialty interesting, as it represents the results of many years' collecting in one set of beds by a good collector living on the spot. The species enumerated were all found by the Rev. E. Jenkinson in the Lowick quarries, which are all in the Upper Bernician Series (= Yoredales), ranging from the Great Limestone at Dryburn to the fifth bed of Lime- stone below it. It is unfortunately impossible now to refer each species to its particular bed, but the whole forms an excellent example of the Upper Bernician fauna at one locality in North Northumberland. The specimens are now in the Woodwardiai* Museum at Cambridge. List of fossils from the Lowick beds (Northumberland), from; Sedgwick and McCoy's " British Paleozoic Fossils " : — Discina bulla, McCoy, from red sandy bed, unique specimen. D. nitida, Phill. sp., (—Orbicula nitida, Phill.), dark limestone. Seminula virgoides, McCoy, rare. Spirifera duplicicosta, Phill., rare. Sp. ovalis, Phill. var. hemispherica, not uncommon. Sp. trigonalis, var. a, trigonalis, Mart, sp., common. Sp. tr., var. b, bisulcata, Sow., rare. Sp. (Martinia) lineata, Mart, sp., very common. Sp. (Martinia) symmetrica, Phill., very common. Athyris ambigua, McCoy, common, of small size. A. gregaria, McCoy, var. a, trapezoidalis, McCoy, rare. A . paradoxa, McCoy, common. Hemithyris acuminata, Mart, sp., var. pugnus, Sow., common. H. pleurodon,PhiU., rare. Camerophoria laticliva, McCoy. Orthis connivens, Phill. sp., rare. O. resupinata, Mart, sp., very rare. Leptoena ( Strophomma) cylindrica, McCoy, common. L. (Chonetes) polita, McCoy, rare. Producta aculeata, Mart, sp., not uncommon. Pr. corrugata, McCoy, rare. Pr. costata, Sow., rare. Pr. elegans, McCoy, not uncommon. Pr.fimbriata, Sow., abundant. Pr. Flemingi, Sow., common. Pr. gigantea, Mart, sp., very abundant. Pr. punctata, Mart, sp., not uncommon. Pr. scabricula, Mart, sp., not uncommon. Pr. striata, Fisch. sp., rare. Producta tortilis, McCoy, not very uncommon. Pecten (?) fimbriatus, Phill., common. P. subelmgatus, McCoy, not rare. Geology of Northumberland. 61 Amusium deornatum, Phill. sp., rare. A. Sowerbyi, McCoy. Pterinea kevigata, McCoy, two young (?) specimens. Pteronites persulcatus, McCoy. Streblopteria kevigata, McCoy, rare, of large size. Str. pulchella, McCoy, rare. Aviculopectm caslatus, McCoy, rare. A. cancellatus, McCoy, rare. A. concavus, McCoy, not uncommon. A. conoideus, McCoy, one specimen. A. dooms, McCoy, common. A . granosus, Sow., sp. A. Ruthvmi, McCoy, one small specimen. A. segregates, McCoy, rare. Lithodomus Jenhinsoni, McCoy, not uncommon. Anodontopsis (?) pristina, M. V. K. sp., rare. Myophoria depressa, Portl. sp., common. My. obliqua, McCoy, common. Pinna flexicostata, McCoy, very common. P. spatula, McCoy, rare. Edmondia Egertoni, McCoy, not very common. E. Jqsepha, de Kon., rare. E. oblonga, McCoy, abundant. E. phaseolina, Gold., sp., not uncommon. E. rudis, McCoy, rare. E. scalaris, McCoy, very rare. E. sulcata, Phill. sp., extremely abundant. E. unioniformis, Phill. sp., rare. Sanguinolites iridinoides, McCoy, very abundant. S. striato-lamellosus, de Kon. sp., rare. S. subcarinatus, McCoy. , S. sukatus, Flem. sp., common. 5. tricostatus, Portl. sp., very rare. S. variabilis, McCoy, not uncommon. Leptodomus costellatus, McCoy, common, in shales. Conocardium aliforme, Sow. sp. Solenomya primtzva, Phill., very common. S. pr., var. b, Puzosana de Kon., not uncommon. Conularia quadrisulcata, Miller MS., one small specimen. Phurotomaria altavittata, McCoy, not uncommon. PI. decipiens, McCoy, rare (two varieties). PI. erosa, McCpy, rare. PI. Griffithi, McCoy, very rare. Murchisonia dispar, McCoy, not very uncommon. Polytremaria catenata, de Kon. sp., rare. Platyschisma glabrata, Phill. sp., very small specimen. 62 Outlines of the PI. helicoides, Sow. sp., common. Straparollus (?) catillus, Mart, sp., rare. Sir. costellatus, McCoy, rare. Str. Dyonysii, McCoy, rare. Str. pentangulatus, Sow. sp., internal casts. Str. tabulates, PhiM. sp., not uncommon. Naticopsis variata, Phill. sp., two specimens. Loxonema rugifera, Phill., very rare. Macrocheilus acutus, Phill., common. M. brevispiratus, McCoy, rare. M. Umnceiformis, McCoy, not very common. M . sigmilineus, Phill., sp., rare. M. (?) spiratus, McCoy, common. Dentalium dentaloideum, Phill. sp., very common. Bellerophon decussatus ( ?) Flem., very large spms., not very rare. B. Dumonti, d'Orb., casts (?).- B. Larcomi, Portl., one specimen. B. Phillipsi, McCoy, rare, casts. B. recticostatus, Portl., one cast. Nautilus bilobatus, Sow., rare. N. coronatus, McCoy, very rare. N. costato-coronatus, McCoy, very rare. Niglobatus, Sow., not very uncommon. N. ingens, Mart, sp., common, of large size. N. oxystomus, Phill., rare. N. quadratus, Flem., common. Aganides reticulatus, Phill. sp., one obscure fragment. Orthoceras Breyni, Mart, sp., not uncommon. O. cordiforme, Sow., rare. O. cornu-vaccinum, McCoy, not very uncommon. O. cylindraceum, Flem., rare. O. Flemingi, McCoy, very rare. O. fusiforme, Sow., not very common. O. giganteum, Sow., very common and of great size. O. inequiseptum, Phill., rare. O. laterale, Phill., not uncommon. O. rugosum, Flem., rare. O. Sowerbyi,, McCoy, not uncommon. O. undatum, Flem., not very uncommon. Diphyphyllum gracile, McCoy, not uncommon. CHsiophyllum prolapsum, McCoy, var. and minor, one specimen. Siphonodendron sexdecimale, Phill. sp., not uncommon. Cladodus striatus, Ag., rare. Cochliodus magnus, Ag., common (?). C. striatus, Ag., very rare. Helodus planus, Ag., rare. Geology of Northumberland. 6$ Leptacanthus Jenkinsoni, McCoy, not very uncommon. Petalodus acuminatus, Ag., not uncommon. P. Hastingsii, Owen, very rare. P. rectus, Ag., not uncommon. Pcecilodus Jonesii, Ag., very rare. Psammodus cornutus, Ag., rare. Ps. rugosus, Ag., rare (var. porosus). Next is a list of the fossils found in two of the beds included in the Lowick series, the occurrence in each bed being here dis- criminated however. N.B. — The Foraminifera will be >given separately. List of fossils found in the "Great'" and "four-Fathom"' Limestones : — Great Four-Fathom Limestone. Limestone. Chmtetes tumidus, Phill. ... * # Aulophyllum fungites, Flem. ... ... # ... :>: Cladochanus bacillaris, McCoy :[: Favosites parasitica, Phill. Lithostrotion irregulare, Phill. Griffithides Farnensis, Tate * Gr., sp Leperditia, sp Spirorbis carbonarius, Murch. ■ '■ ... * Archaocidaris Urei, Flem. Poteriocrinus crassus, Mill. Hydreiapocrinus globularis, de I> Ion. * Glauconome pulcherrima, McCoj J # Gl. pluma, Phill Fenestetta phbeia, McCoy F. membranacea, Phill. ... * ... Lingula mytiloides, Sow. ... * L. squamiformis, Phill. ... * £ L., sp .* Productus fimbriates, Sow. * . •* P. punctatus, Mart. * * P. scabriculus, Mart. .. ... ^ P. Flemingii, Sow. * 1* P. Martini, Sow. ... * * P. semireticulatus, Mart. ... * * P. Cora, d'Orb * * P. latissimus, Sow. * * P- giganteus, Mart. * * Orthis Michelini, Lev. jj; * 0. resupinata, Mart. ."./ ". * * Streptorhyncus crenistria, Phill. * :(= <64 Outlines of the Sty. arachnoidea, Phill * ... _ Rhynchonella pleurodcm (?), Phill. ... * ... * Spiriferina laminosa, McCoy * ... _ S. octoplicata, Sow. ■ * ... _ Spirifer pinguis, Sow _ ... # S. lineatus, Mart * ... * S. Vrei, Flem * ... _ S. glaber, Mart * ... * S. sex-radialis, Phill ' * ... _ S. bisulcatus, Sow. ■* ... * S. trigonalis, Mart. > * ■•• * Athyris ambigua, Sow _ ... * A. piano -sulcata, Phill _ ... * A starte tremula, de Ryck. _ ... * Solemya prvmava, Phill * ... * Area cancellata, Mart. ... ... ... * ... * Z,ei« attenuata, Flem * ... * Ctenodonta undulata, Phill. _ ... * Ci. gibbosa, Flem * ... * Leptodomus costellatus, McCoy * ... ^ SanguinoUtes striato-lamellosus, de Kon. * ... _ 5. constrictus, King * ... _ 5. angustatus, PhilL ... _ ... * S. transversus, Port. # ... _ 5. iridinoides, McCoy ... ... ... $ ... _ S. variabilis, McCoy # ... * Edmondia rudis, McCoy _ ... $ £. sulcata, Phill « ... * E. oblonga, McCoy ,.. * ... * Myophoria depressa, Port _ ... * Liihodomus dactyhides, McCoy ... ... _ ... $ Pinna membranacea, de Kon $ ... _ P.flexicostata, McCoy ... :; -. ... _ P. flabelliformis, de Kon. ". : ; : ... _ Aviculopecten variabilis, McCoy _ ... # j4. tabulatus, McCoy _ ... * ^4. micropteris, McCoy _ ... $ A. duplicostatus, McCoy $ ... _ X. inUrstitialis, Phill : ; : ... :;: /I. concentrico-striatus, McCoy _ ... # A. cancellatus, McCoy _ ... $ 4. tcelatus, McCoy _ ... -;. ' PUronites persulcatus, McCoy _ ... ^ Amusium deornatum, Phill. ... ... * ... $ j4. Sowerbyi, McCoy * ... _ Pecten sub-elongatus, McCoy # ... _ Geology of Northumberland. 65 Conularia quadrisukata, Sow. ... Macrocheilus acutus, Sow. M. spiratus, McCoy M. ovalis, McCoy M. sigmiiineus M. Umnaformis, McCoy Loxonema elongata, de Kon. L. tumida, Phill L: rugifera, Phill L. sulculosa, Phill. Naticopsis plicistria, Phill. N. spirata Euomphalus tabulatus, Phill. E. Dionysii, Golf. £. costellatus, McCoy £. carboparius, Sow Murchisonia quadricarinata, McCoy M. angulata (?) Phill ... M., sp. ... Pkurotomaria monilifera, Phill P. decipiens, McCoy P. atomaria, Phill Capulus trilobatus, Phill Belkrophon Urei, Flem B. striates, Flem £. decussatus, Flem B. navicula, Sow Actinoceras giganteum, Sow. Poterioceras cornu-vaccinum, McCoy Orthoceras undulatum Sow. O. sulcatum, Flem. O. attenuatum, Flem O. cylindraceum, Flem O. inequiseptum, Phill O. pyramidale, Flem. O. Goldfussianum, de Kon. ' Nautilus ingens, Mart N. globatus, Sow JV. bilobatus, Sow * W. costato-coronatus, McCoy iV. subsulcatus, Phill JV. biangulatus, Sow iV. sulcatus, Sow N. perplanatus, Portl Psammodus cornutus, Ag Rhizodus Hibberti, Ag. * * * * _ * _ * * _ * _ * * * * _ * * * _■ * „ * _- * * — •i- * * _ * _ * _ * * _ * __ * * * .. _ * • • _ * * * _ * - • * _ * 5fc _ * -_ *: _ * 66 Outlines of the The succeeding list gives a good idea of the fauna of the Berni- cian beds in that part of them which corresponds to the Scar Limestone Series. Many more species will probably be added to this list, as the locality is extremely rich in fossils and has by no means been collected out. It may be mentioned here that in a bed of limestone still lower in the series the genu's Agdacrinus, one usually limited to Silurian rocks, has been found. An account of this fossil is to be found in the Annals of the Belgian Geological Society for 1876, and the specimen is now being described by a competent naturalist. It appears to be very closely allied to, if not identical with, Ag. squamosus of Meek and Worthen, a species represented by one single American Carboniferous specimen. List of Fossils from the Ridsdale ironstone beds, Northumber- land : — Chwtetes tumidus, Phill. Ch., sp. Cyathophylluvo., sp. Clisiophyttum; sp. FavosiUs, sp. / Lithostrotion irregulars,- Phill. Lithodmdron junceum, Flem. L. floriforme. Syringopora geniculata, Phill. Poteriocrinus (?), sp. P. crassus. Rhodocrinus, sp. Woodocrinus, sp. Archeocidaris, Urei. Arch., sp. HemitrypaHibernica; McCoy. Polypora papillata, McCoy. Ceriopora, sp. Fenestella plebeia. F., sp. Athyris Royssii, L'EveillS. Discina nitida, Phill. Lingula mytiloides, Sow. L. Scotica, Dav. L. squamtformis, Phill. Orthis resupinata, Mart. Orth., sp. Productus Cora, d'Orb. Pr. giganteus, Mart. Pr. longispinus, Sow. Geology of Northumberland. 67 Pr. I., var. lobatus, Sow. Pr. scabriculus, Mart. Pr. undatus, Defr. Pr. Martini. Rhynchonella pugnus, Mart. : Spirifera glabra, Mart. S. lineata, Mart. ■ S. laminosa, McCoy. - Strophomena analoga, Phill. Terebratula sacculus, Mart. Chonetes Hardrensis (Phill. sp.) Ch., sp. Aviculopecten planoradiatus, McCoy. A. papyraceus, Sow. A. concdvus, McCoy. A. ccelatus, McCoy. A., new sp. Pinna flexicostatd, McCoy. P., sp. P., sp. Anthracosia acuta, Sow. j4«j»ms sulcatus, Sow. /4#. axiniforniis, Portl. ;4.£. carbonarius, Sow. Dolabra equilateralis, McCoy. Ctenodonta tumida, Phill. Leda attenuate, Flem. Edmondia arcuata. E. quadrdta, McCoy. E. sulcata, Phill. Mytilus Fhmingii, McCoy. Myacites Austinei, Sow. M. primoeva, Portl. M. sulcata. M., sp. , Sanguinolites curtus, McCoy. S. irridinoides, McCoy. S. plicatus, Portl. S., sp. Conularia qttadrisulcata, Sow. Macrocheihis canaliculars, McCoy. Euomphahts, sp. Bellerophon decussatus, Flem. B. Urei, Flem. B., sp. Goniatites obtusus, Phill. 68 Outlines of the G. spharicus, de Haare. G. truncatus, Phill. G., sp. Cyrtoceras Gesneri, Mart. Discites sulcatus, Sow. Orthoceras ovale, Phill. Or., sp. Discites subsulcatus. D., sp. Cladodus striatus, Ag. Gyracanthus tuberculatus, Ag. Helodus Icevissimus, Ag. Psammodus reticulatus. P. porosus, Ag. P., sp. Specimens of all these species from this rich locality are preserved in the Museum of the College of Physical Science. The interesting fossil Posidonomya Beckeri occurs at Budle and in the neighbourhood of Alnwick, and appears to be confined to the Upper Bernician Series. Its exact horizon is doubtful. The two next lists are very complete as to the microzoa, and for them I have to thank the Rev. Mr. Howchin, F.G.S., of Halt- whistle, who kindly washed the material collected by me, and determined the species. The Scremerston Limestone is one of the lowest in the series, while that at Lamberton is the " Dun Limestone " which, as has been explained already (p. 44), is taken as the base of the Bernician rocks. A list of fossils observed in a washing taken from a band in the Scremerston Limestone, South of Berwick : — Climacammina antiqua, Brady, very rare. Endothyra Bowmani, Phill., rare. E. radiata, Brady, rather scarce. Stacheia polytrematoides, Brady, rather scarce. Textularia eximia, d'Eich., very rare. Trochammina incerta, d'Orb., common. Valvulina palteotrochus, Ehreub., rare. „ „ var. compressa, moderately common. V. decurrens, Brady, common. V. plicata, Brady, very rare. Stenopora tumida, Phill. Archaocidaris sp., various small spines. Encrinital remains. Spirorbis globosus (?), McCoy. Geology of Northumberland. 69 Entomostraca, common. Glauconome flexi-carinata, Y. and Y. Hyphasmopora Buskii, Eth. Rhabdomeson gracile, Y. and Y. Rh. rhombiferttm, Y. and Y. Chonetes Buchiana (?), de Kon. Lingula, sp. Productus semireticulatus, Mart. 'Spirifera glabra, Mart. Sp., sp. Streplorhynchus crenistria, Phill. Loxonema polygyra (?), McCoy, cast. Ctenoptychius serratus, Ag. Numerous small fish remains. A list of Fossils observed in a' washing taken from the Lamberton Limestone, three miles North of Berwick : — Archadiscus Karreri, Brady, rare. Endothyra radiata, Brady, rare. Saccammina Carteri, Brady, single specimen. Stacheia acervalis, Brady, rare. St. congesta, Brady, rare. St. fusiformis, Brady, rare. St. pblytrematoides, Brady, rather scarce. Trochammina incerta, d'Orb, very common. Valvulina decurrens, Brady, moderately common. V. palceotrochus, Ehrenb., common. V., var. compressa, rare. V. plicata, Brady, rather scarce. Stenopora tumida, Phill. Archaocidaris, sp., plates. Encrinital, stems, etc. Ortonia carbonaria, Young. Spirorbis, sp. Entomostraca, rather scarce. Ceriopora interporosa, Phill. Fcnestetta, sp. Glauconome marginalis, Y. and Y. Gl. retroflexa, Y. and Y. GL, sp. Hyphasmopora, sp. Polypora, sp. Sulcoretepora parallcla, Phill. Spirifera, sp. Productus giganteus, extremely abundant. 7© Outlines of the Bernician Foramimfera of Northumberland, after H. B. Brady, F.R.S. :— Archtediscus Karreri, Brady. Bigenerina patida, Brady. Lower Bernician (= Scaur Lime- stones). Upper Bernician (= Yoredalfr Beds). Upper and Lower Bernician. Endothyra ammonoides, Brady. E. Bowmani, Phill. £. crassa, Brady. E. globulus, Eichw. E. macella, Brady. E. obliqua, Brady. E. ornata, Brady. E. radiata, Brady. Lagena Howchiniana, Brady. L. Lebouriana, Brady. L. Parkeriana, Brady. Lituola nautiloidea, Lam. Saccammina Carteri, Brady, — (characteristic of the Four- Fathom Limestone, but also found at other horizons). Stacheia acervalis, Brady. St. congesta, Brady. St. fusiformis, Brady. St. polytrematoides, Brady. St. pupoides, Brady. Textularia eximia, Eichw. T.gibbosa, d'Orb. Trochammina anceps, Brady. Tr. annularis, Brady. Tr. centrifuga, Brady. Tr. gordialis, Park and Jones. Tr. incerta, Brady. Valvulina palceotrochus, Ehreub. V. plicata, Brady. V. Youngi, Brady. We conclude with a list of those Carboniferous Limestone fossils which are quoted by d'Orbigny as occurring in Northum- berland. Carboniferous fossils recorded from D'Orbigny's Prodr6me, (1850) : — Lower Bernician. Upper and Lower Bernician. Upper Bernician. Upper and Lower Bernician. Upper Bernician. Lower ,, Upper and Lower Bernician. Upper Bernician. Upper and Lower Bernician. Upper Bernician. Upper and Lower Bernician. Upper Bernicians. Upper and Lower Bernician. -, " n ." " Lower Bernician. Northumberland in * See Brady's "Monograph of Carboniferous and Permian Foramimfera." Pateontographical Society's Publications for 1876. Geology of Northumberland. 7 1 In this list the locality " Harelaw " is supposed, in some cases, to be a misprint for Hareshaw. Nautilus Phillipsianus, d'Orb. (=sulcates, Sow, 1826, non sukatus, Risso, 1825). N. tetragonus, Phill. Cyrtoceras rugosum, de Kon. (=Orth. annulatum and rugosum, Phill.) Loxonema rugifera, Morris (—Chemnitzia rug., de KoH., and Melonia rug., Phill.) Macrocheilus acutus, Phill. (—Buccinum acutum, Sow., M. ovdlis r McCoy, and Littorina pusilla, McCoy). Natica elliptica, Phill. N. plicistria, Phill. (=Nerita plicis., de Kon.) N. ampliata, Phill. (=Nerita ampl., de Kon.) Straparolus pentcmgulatus, d'Orb. (=Euomphalus pent.. Sow.) Str. tabulatus, d'Orb. (=Euomph. tabulates, Morris, and Cirrus tab- ulates, Phill.) Murchisonia triserialis (?) d'Orb. (=Turitella triser., Phill.) Pleurotomaria vittata, Phill., Otterburn. Pholodomya sulcata, d'Orb. {=Sanguinolaria sulc., Phill.) Lyonsia arcuata (?). d'Orb. (=Sanguinolaria arcuata, Phill.), Harelaw. Sokmya primava (?), Phill. Ltda clavifOrmis, d'Orb. (=Nucula clavif., Sow.), Harelaw and Otterburn. £,. brevirostris, d'Orb. (=Nucula brevir., PhilL), Harelaw. Cypricardia tumida, d'Orb. (—Nucula turn., Phill.) C. rhombea, Phill. (=Cy.glabrata, Phill. and C. bipartita, de Kon.) Cardiomorpha elliptica, de Kon. (=Vmus elliptica (?), Phill.) C. axiniformis, d'Orb. (—Isocardia axiniformis, Phill., and Nucula luciniformis, Phill.) Pinna granulosa, d'Orb. (=Modiola granul., Phill.) Lingula parallela, Phill. Productus giganteus, Sow. 1 Pr. latissimus, Sow. Pr. Cora, d'Orb., Lowick. Pr. semireticulatus, Flem. Pr. costates, Sow, Lowick. Pr. Flemingii, Sow. Pr. scabriculus, Sow., Harelaw. Pr. punctatus, Sow., Otterburn and Lowick. Pr. fimbriates, Sow. Chonetes sulcata, de Kon., Lowick. Ch. tuberculata, de Kon. (=Leptana tuberc, McCoy), Lowick. Strophomena depressa, d'Orb. ( =: Leptagonia depressa, McCoy, Producta depressa, Sow. and Leptmna depressa, de Kon.) 72 Geology of Northumberland. Spirifcra duplicostata, Phill. (—Sp.furcata, McCoy). Sp. integricosta, Phill. Sp. duplicicosta, -Phill. Sp. trigonalis, Sow. (=Sp. transients, McCoy). Sp. bisulcata, Sow. (—Sp. semicircularis, Phill.) Spirigera ambigua, d'Orb. (= Spirifer ambiguus, Sow., and Tere- bratula ambigua, de Kon.) Terebratula sacculus, Mart. (= Ter. hastata), Phill., Otterbum. Orbiculoidea nitida, d'Orb;, Harelaw, Otterbum. Diphyphyllum irregulare, d'Orb., (= Lithodendron irreg. Phill. Chetetes septosus, de Keys. (= Favosites septosus, Flem.) 73 TOPOGRAPHICAL INDEX. Acklington, 29, 47-49, 56. Acomb, 12, 38. Acre, 36, 39. Adderstone, 9. Allendale, West, 50. Allenheads, 36. Allerdean, 39. All er wash, 35. Aln, zz, 16. Alnmoutb, g. Alnwick, 13, 33, 54. Alston Moor, 33-36, 38, 41, 52. Alwin, 6, 48, 58. Alwinton, 6, 45, 57. Andrew's Close, 38. .Angerton, 8, xo. Bamburgh, g, 13* Bamburgh Castle, 54. Bardon Mills, 36, 41. Barrow Scroggs, 45. Bavington, 16, 53. Bavington Hall, 50. Beacon, The, 42. Beadnell, 36, 39, 49. Beadnell Bay, 54. Beal, 9. Bedlington, 49. Belford, 55. Belling, The, 50. Bellingham, 38. Belsay, 34. 38. Benwell Hill, 24. Berry Hills, 52. Berwick, g, 13, 38, 44, 51. Biddlestone, 43, 45, 48, 56. Biddy Mill, 48. Billsmoor, 41, 50, 51. Bingfield Burn, 50. Black Burn, 51. Black Law, 58. Blanchland, 32, Blaydon, 28. Blenkinsopp, 38. Blindburn, 56. Blyth, 22. Blyth, River, 9, 16. Bogball, 38. Bolam, 50. Boldon, 26. Bondicar, 49. -Boulmer, 51. Bradford, 13, 14. Breamish, 7, 56. Brier Edge, 38. Brinkburn, 36. Brockley Whins, 26. Brownlees, 38. Brunton, 50. Budle, 9. Burnt Divot, 8. Burradon, 24. Byker, 24, 49. Cairnglastenhope, 8. Callalee, 41. Cambo, 38. Carbarn, 13. Carritetb, 38. Carrycoats, 38. Carter Fell, 42, 57, 58. Cartington, 49. Cawledge Mill, 9. Cbathill, 14. Cheviot, 56. v Cheviots, The, 3-8, 16, 43, 55-58. Chevy Chase Road, 46. Chillingham, 44. Cbirdon Burn, 9. Chirm, 35, 39. Cbollerton, 16, 53. Chopwell, 32. Cbristenbury Crags, 42. Clarewood, 38. Cleadon, 48, 49. Clennell, 48, 49, 56. Clennell Street, 57. Closing Hill, 20, 26. Clyde, 14. Coal House, 50. Coldstream, 51. Coley Hill, 48, 49. Condercum, 24. Coquet, 6, 7, 11, 15, 16, 29, 32, 33. 35, 41, 42, 45, 49, 56- Coquetdale, 4, 45, 56. Corbridge, 4, 5, 16, 2g, 34, 41. Cornhill, 51. Cottonshope Head, 57. Cowden, 38. Cramlington, 27, 49. Cross Fell, 37« Cullercoats, 4, x8, 19, 20, 24, 58. Cumberland, 4, 29, 42. 74 Darden Lough, 8, 51. Deadwater Fell, 42. Denton, 4, 27. , Derweut, 8, 12, 24, 28, 31, 32. Derwentcote, 32. Dewley, 49. Drake Stone, The, 42. Drybum, 39, 60. Dunstanburgh, 54. Durham, 18, 22, 23, 26-28. Dyke Head, 53. Dykenook, 6. East Woodburn, 15, 41. Eden, 11. Eelwell, 37, 39. Eglingham, 40. Erf Hills, 36, 53, 55- Ellis Crag, 42. Elsdon, 6, 8, 38, 50. ElsdoD Burn, 50. Elswick, 7. Embleton, 54. Erring Burn, 16. Fallowlees Burn, 54. Falistone, 51. Fame Islands, 54. Fleetham, 39. Font, 7, 37, 50. Forest Bum, 54. Fourstones, 41. Gallow Hills, 53. Gateshead, 12, 23. Glororura, 14. Goldstone, 49. Gosforth, 22, 24. Grasslees, 42. Great Whittington, 38. Greeneyes Crag, 38. Greenhead, 51. Greenlee Lough, 38. Greenleighton, 54. Greenses, 39. Greenside, 4. Gunnerton, 38. Haltwhistle, 8, 11, 36, 38, 41. Haltwhistle Burn, 36. Hampeth Burn, 51. Harbottle, 6, 41-44. Harelaw, 71. Haresbaw, 50. - Hareshaw Head, 38. Harkess Rocks, 54. Harlow Hill, 32, 34, 59. Hartington, S3- Hartley, ig, 20, 23. Hart side Pike, 41. Haswell, 27. Haughton Castle, S3* Haydon Bridge, 11, 35, 36, 50. Heaton Mill, 51. Hebburn, 48, 51. > Hedworth, 48. Hepple, 45. Hetchester, 45. Hetton, 27. Hexham, 38. High Carrick, 50. High Green, 50. Hindhope, 58. Hobberlaw, 39, 54. Holy Island, 9, 10, 13, 47, 49. Homilton, 53. Horsley (Redewater), 6, 42. Howgate, 39. Howick, 10, 51. Inghoe, 34, 33, 37. 38, 4°t 41. Ingleborough, 31. Irthing, 8, 10, 11, 42. Jarrow Slake, 9. Kenton, 24. Killingworth, 20, 24, 26. Kinderscout, 31. Kirk-Whelpington, 53. Knowes Gate, 52. Knucton, 55. Kyloe, 50, 55. Lamberton, 44. Leitham, 50. Lewis Burn, 3g, 50. Licker, 35, 39. Lindisfarne, 49. Linnsheolcs, 42. Lippwood, 36. ~ Lisle Burn, 15. Little Bavington, 38. Lough House, 10. Lowdean, 36. Lowick, 5, 36, 3g, 50, 60. Low Teppermpor, 52. Lucker, 14. Lumsdon, 7. Makendon, 46, 57. Matfen, 34, 35, 37. Mattalees, 51. , Medomsley, 28. Middleton (in Wansbeck Valley), 10. Middleton (near Wooler), 9, 55. Milkington, 51. Minsteracres, 4. Mitford, 16, 32. Monkridge, 7. Morpeth, 7, 11, 16, 28, 32. Newcastle, 4, 23, 24, 25, 49. Newham, 14. Newminster, 11. Newnharo, 49. Newsham, 22. Newton, 10. Newton North Farm, 54. Newton Underwood, 37. North Seaton, 26. North Shields, 18. North Sunderland, 10, 37. North Tyne, 7, 8, 9, 10, 12, 15, 42, 44, 50, 52, 53- Oak wood, 38. Old Newton, 54. Otterbum, 7. Ovingham, 32. Peel Fell, 42. 75 Penine Chain, 8, 37.. Peppermoor, 54. Philip, 46. Plashetts, 6; 38, 51. Plessey, 28. Plough Rock, 49. Pont, 10, 50. Ponteland, 10. Prestwick Carr, 10. Prudhoe, 59. Ramshope, 56. Ratcheugh, 54. Redesdale, 4, 6. Redesmouth, 15. Redewater, 7, 10, 15, 42, 46, 56 Redheugh, 10, 12. Riccarton, 46. Ridlees, 56, 57. Ridlees Burn, 57, Ridsdale, 66. Rochester, 42. Roddam Dene, 43. ' Rothbury, 16, 41, 42, 55, 56. Rothley, 34. Rowlands Gill, 16. Ruben Law, 58. Rugley, 54. Ryho^e, 23. Salt wick, 31. Scot's Gap, 36, Scremerston, 33. Seaton Burn, 24. Seaton Sluice, 18-20, 24, 48 Shafthoe, 34. Sharperton, 45. Shilbottle, 39, 49, 51.. Shilburnhaugh, io, 38, 39 Shillmoor, 49. Short Cleugh, 50. ' Silly Burn, 35. Simonside Hills, 8, 41. Slatyford, 49. Soppit, 38. South Shields, 10. South Tyne, 7, 8, 11, I2 r 34, 35, 50, 52. Spindlestone, 55. Spittleford, 54. St. John Lee, 12. St. Margaret's Farm, 54. St. Mary's Haven, 54. St. Mary's Island, 9, 24. St. Oswald's Chapel, 50. Starslee, 39. Stiddle Hill, 38. Stocksfield, 31, 59.. Stublick, 4, 5, 29. Sweethope, 52. Swinburne Mill, 52. Swinhoe, 39. Swire, The, 6. Tarret Burn, 50, 51. Tarset, n. Team, 12. Thorngrafton, 16. . Till, 7, 12. Tosson, 51. Town. Moor, 49. Tdwneley, 28. Trobe's Dene, 49. Trough End, 50. Tyne, 4, Q-I2, 16, 26, 29, 31-34. 4*. 48- Tynedale, 4. Tynemouth, 9, 18, 48. Tweed, 13, 44, 47. "Walker, 48. Wallington, 8. Wallsend, 27. Wanney Crags, 41. Wansbeck, 7, 8, 10-12, 16, 27, 32, 34*. 35. 4i. 46. 49. 52. Ward's Hill, 54, 55. Warden Hill, n. .Wark, 38. Wark's Burn, 30. Warkworth, 27, 31, 32. Watling Street, 50. West Allendale, 50.. Whetstone House, 15. Whickhope Burn, 10. White Law, 57. Whitelee, 46, 58. Whitfield, 50. Whitley, g, 18, 23. Whittington, 35. Whittonstall, 4,(28, 31, 59.. Whorlton, 49. ' Widdrington, 29. Wide-Open, 24. \ Wolsington, 28. Woodburn, East, 15.. Woodhorn, 29. Wooler, 9, 56. Wylam, 16, 24, 28.. Yevering, 56, 57. Illustrations of Fossil Plants: An Autotype Reproduction of Selected Drawings, prepared between the years 1835 and 1840, by the late Dr. Lindley and Mr. W. Hutton. Edited by G. A. Lebour, F.G.S. Royal 8vo., 65 Plates. (1877). Price £1 5s. 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