19 Q 3 BOUGHT WITH THE INCOME PROM THE SAGE ENDOWMENT FUND THE GIFT OF 3-1 cur ij m. Sage 1891 Immjc flfflte 3777 Cornell University Library QE 262.S16R35 1903 The geology of the country around Salisb 3 1924 004 552 984 Cornell University Library The original of this book is in the Cornell University Library. There are no known copyright restrictions in the United States on the use of the text. http://www.archive.org/details/cu31924004552984 298. MEMOIRS OF THE GEOLOGICAL SUEVEY. ENGLAND AND WALES. THE GEOLOGY OF THE COUNTKY ABOUND SALISBURY. (Explanation of Sheet 298.) BY CLEMENT REID, F.R.S., F.L.S., F.G.S., With contributions by H. B. WOODWARD, F.R.S., F. J. BENNETT, F.G.S., AND A. J. JUKES-BROWNE, B.A., F.G.S. f rVBMSHED BY ORDER OF THE LORDS COMMISSIONERS 0* HIS MAJESTY'S IRKASOKlf. LONDON : PRINTED FOR HIS MAJESTY'S STATIONERY OFFICE, By Wyman ani> Sons, Limited, Fetter Lane, E.C. And to be purchased from E. STANFORD, 12, 13, and 14, Lono Acre, London; JOHN MENZIES & Co., Rose Street, Edinburgh; HODGES, FIGGIS & Co., Grafton Street, Dublin ; From any Agent for the sale of Ordnance Survey Maps ; or through any Bookseller from the Ordnance Survey Office, Southampton. 1903. Trice Is. 3d. (Price of Sheet W8, colowr-prmted, la. 6d.) ^m%% de- list OF MAPS, SECTIONS, AND OTHER PUBLICATIONS OF THE GEOLOGICAL SURVEY OF ENGLAND AND WALES. The Maps are those of the Ordnaacs Survey, geologically coloured_by the Geological Survey of the United Kingdom, under The Superintendence of J. J. H. TEAM, F.R.S., Director. ; For Maps, details of Sections, and Memoirs issued by the Geological Survey, see " Catalogue." • ENGLAND AND WALES.-(Seale 1 inch to a mile.) Maps marked * are also published as Drift Maps. Those marked t are published only as Drift Maps. Sheets 3*, 6, 6*, 7*, 8*, 9, llj to 22, 25, 26, 30, 31, 33 to 37, 40, 41, 44, 47*, 64*,'65t, 69t, 70*, 88*, 86*, priee 8e. 6*. each. Sheets 4, 5». . Sheets 2*, 23, 24, 27 to 29, 32, 38, 39, 58, 84t, 85t, is. each, Sheets divided into quarterSi: all at 3s. each quarter-sheet, excepting those in brackets,,which are, 1*. id. each. 1* 42, 43, 45, 46, NW, SW, KB*, SB*, 48, NWt, SW*, NEt, 1 (SE*), (49t), 5flt, 51,*, 52 to 57, (57 NW). 59 to 63, 66 SWt,. NEt, KW», SEt, 67 Nt, (St), 68 Et, (NWt), SWt, 71 to 75, 76 (N), S, (77 N), 78, 79, NW*, SW, NE*, SE*, 80 NW*, SW*, NE*, SE*„8i NW», SW.NB, SE, 82, 83*, 87, 88, NW. SW*, NE, SB, 89 NW* SW*. NB, SE*, 90 (NE*), (SE*), 91, (NW*), (8W»), JJE*, SB*, 92 NW*, SW*, NE, SE, 93 NW, SW, NB*, SE*, 94 NWt, SWt, (NEt), SEt, 95 NW*, NE*, (SB*), 96 NW*, SW*, NE*, SE*, 97 NW*, SW», NE*, SE, 98 NW, SW,. NE*, SE, 99 (NE*), (SE*), 100*, 101, SE, NE*, NW», SW*, 102 NW* NE*, SW*, SE*, 103*, 104*, 105 NW*, SW*, (NE*); SE* 106 NW*, SW* NE*, SE*, 107 SWt, NE*, SB*, 108 SW*, NE*, SE*, 109 NW», SW*, SE*, 110 (NW*), (NE*), SE* SW*. „ Xao Series.— X. of Man*, 36, 45, 46, 56, 57, 8s. 6d. I. of Wight, with Mainland*, 380, 331, 344, 345, 8s. 64. (128*), 155% 187£ 203t, 231*, (232*), (248*), 249*, 261 and 262*, 263», 267t, 268* 282t, 283t, 284t, 299t, 300t, (314t), 315t, 316t, 325t, 328t, 329*,, 380*, 331*, (332*), (333*), 334*, 339t, (340t;, (841 1), 342t, 343t, 349t, 350t, 355f , (356t), Price 3s. each, excepting those in brackets!;. which are Is. 6a. each. , - " CEKESAL HEAP :— (Scale 4 miles to 1 inch.) ENGLAND AND WALES.— Sheet 1 (Title) ; 2 (Northumberland, &c.) ; 3 (Index of Colours) ; 4 1, of Man) ; 5 (Lake District)'; ' 6 (E. Yorkshire) ;" 7 (N. Wales) ; 8 (Central England) ; 9 (Eastern Counties) ; 10 (S. Wales and N. Devon) ; 11 (W. of England and S.E. Wales); 12 (London Basin and Weald); 13 (Cornwall, &c.y, 14 (S. Coast, Torquay to' I. of Wight); '» 15 (S. Coast, Havant to Hastings). - jVcw. Berks, printed in eolows, sheet 1, 2s.- ; sheets 2 to 15, 2s. 6(J. each. HORIZONTAL SECTIONS. 1 to 140, 146 to 143, England, price 5s. each. VERTICAL SECTIONS. 1 to 83,. England, price 3s. 6d. each. COMPLETED COUNTIES OF ENGLAND AND WALES, on a Scale of 1 inch to a mile. Old Series. Sheets marked * have descriptive Memoirs. Sheets or Counties marked t are illustrated by General Memoirs: ANGLESEY t,— 77 N, 78. BEDFORDSHIRE,-^ NW, NE, SWt, SEt, 52 NW, NE, SW, SE. BERKSHIRE,— 7*, 8t, 12*, 13*, 34*, 45 SW*. ■BRECKNOCKSHIRE!,— 36,' 41, 42, 56, NW, SW, 57 NB, S'E. BUCKINGHAMSHIRE,— 7*, 13*, 45* NE, SE, 46 NW, SWt, 52 SW. CAERMARTHENSHIREt,— 37, 38, 40, 41, 42 NW, SW, 56 SW, 57SW.SE. CAERNARVONSHIREt— 74 NW, 75, 76,77 N, 78, 79 NW, SW. , - . ■ : / CAMBRIDGESHIRE^— 46 NE, 47*, 51*,, 62 SE, 64*. CARDIGANSHIRE t,— 40, 41, 56 NW, 57, 68, 59 SE, 60 SW. CHESHIRE,— 73 NE, NW; 79 NE, SE, 80, 81 NW*, SW*, 88 SW. CORNWALL t,— 24 1, 26+, 26t, 29t, 30t, 31t, 32t, dV33t. CUMBERLAND,— 98 NW, SW*, 99, 101, 102, NE, NW, SW*, 106 SE, SW, NW, 107. DENBIGHf,-73 N W, 74, 75 NE, 78 NE, SE. 79*NW, SW, SE, 80 SW. 1 DERBYSHIREt,— 62 NE, 63 NW, 7L NW, SW, SE, 72 NE. 72 SE, 81, 82,88, SW, SE. DEVONSHIREt,-^20,t, 21t, 2%, 23\, 24t, 26t, 26t, & 27t. DORSETSHIRE'S, 16, 17, 18, 21, 22. ' DURHAM,— 102 NEf SE, 103, 105 NE, SE, SW, 106 SE. ESSEX,— 1», 2*, 47*,. 48*., FLINTSUIREt,— 74 NE, 79. , GLAMORGANSniREt,— 20, 36, 37, 41, & 42 SE, SW. GLOUCESTERSHIRE^— JS>,'34*, 35, 48, NE, SW, SE, 44*. HAMPSHIRE,— 8t, 9t, 10*, lit, 12*, 14, 15, 16. HEREFORDSHIRE,— 42 NE, SE, 43, 55, 56 NE, SE.. HERTFORDSHIRE,— It NW, 7*, 46, 47*. HUNTINGDON,— 51 NW, 52 NW, NE, SW, 64*, 66. KENTt,-lt SW & SE, 2f, 3t, 4», 6*. LANCASHIRE,-79 NE, 80 NW*, NE, 81 NW, 88 NW, SWt, 89, 90, 91,92 SW. , See also Sew LEICESTERSHIRE,— 53 NE, 62 NE, 63* 64* 70*, 71 SE, SW. ■ LINCOLNSHIREt,— 64*, 66*, 69, 70*, S3*, 84*, 85*, 86*. MERIONETHSHIREt— 69 NE, SE, 60 NW, 74, 75 NE, SE. MIDDLESEXt,— It NW, S.W, 7*, 8t. MONMOUTHSHI»E,^-35, 36; 42 SE, NE, 43 SW. MONTGOMERYSHIRE^— 56 NW, 59 NE, SE, 60, 74 SW SE. NORFOLKt,— 50 NW, NE*, 64*, 65*, 66*,' 67*, 68* 69. NORTHAMPTONSHIRE,— 64*, 45 NW, NE, 46 NW, 52 NW ,NE, SW, 53 NE, SW, & SE, 63 SE, 64. NORTHUMBERLAND,— 102 NW, NE, 105, 106, 107, 108*, 109 . 110. NW*, SW* NE*, SE. NOTTINGHAM,— 70*, 71* NE, SE, NW, 82 NE*, SE*, SW 86, 87* SW. OXFORDSHIRE,— 7*. 13* 34*. 44*, 45*, 53 SE*, SW. PEMBROKESHIREt,— 38, 39, 40, 41, 68. RADNORSHIRE,— 42 NW, NE, 56, 60 SW, SE. RUTLANDSHIRE,— this county is wholly included within Sheet 64*. SHROPSHIRE.-66 NW, NE, 66 NE, 60 NE, SE, 61, 62 NW, 73, 74 NE, SE. SOMERSETSHIRE t,— 18, 19, 20, 21, 27, 35. STAFFORDSHIRE*,-54 NW, 55 NE, 61 NE, SE, 62, 63 NW, 71 SW, 72, 73 NE, SE, 81 SE, SW. SUFFOLK,— 47*, 48*, 49*, 60*, 61*, 66* SE*,j67*. SURREY— 1 SWt, 6t, 7*, 8t, 12t. SUSSEX,— 4*, 6t, 6t, 8t, 9t, lit. WARWICKSHIRE.-44* 46 NW, 53», 54, 62 NE, SW, SE 63 NW, SW, SE. WESTMORLAND.-97 NW*, SW*, 98 NW, NE* SE* 101 SE*, 102. ' WILTSHIRE.-12*, 18*, 14, 15, 18, 19t, 34*, and 35t. WORCESTERSHIRE.-43 NE, 44*. ' 64, 56, 62 SW, SE. 61 SE. YORKSHIRE!,-85-88, 91 NE, SE 82-97* 98 NE* SB* 102 NE SE, 103SW.SE 104. Series Maps. 298. MEMOIRS OF THE GEOLOGICAL SURVEY. ENGLAND AND WALES. THE GEOLOGY OF THE COUNTRY AROUND SALISBURY. (Explanation of Sheet 298.) BY -CLEMENT REID, F.R.S., F.L.S., F.G.S., With contributions by H. B. WOODWARD, F.R.S., F. J. BENNETT, F.G.S., and A. J. JUKES-BROWNE, B.A., F.G.S. PUBLISHED BY ORDER 0» THE LORDS COMMISSIONERS OF HIS MAJESTY'S TREASURY. LONDON : PRINTED FOR HIS MAJESTY'S STATIONERY. OFFICE, By Wyman and Sons, Limited, Fetter Lane, E.C. And to be purchased from E. STANFORD, 12, 13, and 14, Lono Acre, London; JOHN MENZIES & Co/, Rose Street, Edinburgh ; HODGES, FIGGIS & Co., Graeton Street, Dublin; From any Agent for the sale of Ordnance Survey Maps ; or through any Bookseller from the Ordnance Survey Office, Southampton. 1903. Price Is. Sd. (Price of Sheet 298, colow-printed, Is. 6d.) SU^35 PREFACE. The country described in this Memoir includes a large part of Salisbury Plain and part of the Vale of Wardour. The original Geological Survey was made by H. W. Bristow, and published on the old series sheets 14 and 15, in 1856 and 1857, without any accompanying Memoir. The re-survey on the six-inch scale was commenced by Mr. A. J. Jukes- Browne in 1890, and resumed by Mr. F. J. Bennett in 1894, under the superintendence of Mr. Wbitaker. Mr. Bennett, who surveyed most of the ground, retired in 1899, and the field work in the Vale of Wardour was completed in 1900 by Mr. Clement Beid, to whom the preparation of the Memoir has been entrusted. Few notes were left by Mr. Bennett, and Mr. Keid has availed himself of materials gathered by Mr. H. B. Woodward, and published in the General Memoir on the Jurassic Rocks, and of those by Mr. A. J. Jukes-Browne, some of whose observations have been published in the Memoir on Cretaceous Rocks, vol. i., or preparecffor the later volumes. As the Portland and Purbeck strata of the Vale of Wardour extend a little way beyond the limits of the map, it has been deemed desirable to include descriptions of all the sections in the present Memoir. While recognising our indebtedness to previous workers notably to Fitton, whose early observations made the Vale of Wardour classic ground for geologists, as well as to Brodie, Prestwich, Mr. W. H. Hudjeston, Prof. J. F. Blake, Dr. C. Barrois, and others, it is a satisfaction also to acknowledge the personal assistance rendered by the Rev. W. R. Andrews (formerly of Teffont Evias), and by Dr. H. P. Blackmore, of Salisbury, whose intimate knowledge of the Chalk, the Pleistocene, and later accumulations is so well known. J. J. H. TEALL, Director. Geological Survey Office 28 Jermyn Street, London. 18th October, 1901. 6152. 500. Wt 1859. 1/03. Wy. & S. 378r. CONTENTS. PACK. Preface by the Director ; iii Chapter I. — Introduction - 1 Chapter II. — Kimeribge Clay 4 Chapter III.— Portland Beds 5 Chapter IV. — Ptjrbeck Beds- 16 Chapter V. — Wealden - 30 Chapter VI.— Lower Greensand - - 31 Chapter Vfl.— Gault and Upper Greensand (Selbornian) 37 Chapter VIII. — Chalk 45 Chapter* IX. — Eocene 61 Chapter X. — Drift - 64 Chapter XL— Economic Geology 71 Index - 74 LIST OF ILLUSTRATIONS. Pig. 1. Pecten lamellosus, Sow. 6 „ 2. Cerithium portlandicum, Sow. 6 „ 3. Cardium dissimile, Sow. 7 „ 4. Trigonia gibbosa. Sow. 7 „ 5. Ammonites [Perisphinctes] giganteus, Soto. 7 „ 6. Perna mytiloides, Lam,. - 7 „ 7. Lucina portlandica, Sow. - 7 „ 8. Cytherea rugosa, Sow. 7 „ 9. Cyprina elongata, Blake 7 „ 10. Exogyra brurttrutana, Thurm. 7 „ 11. Isastraea oblonga, Flem. - 7 „ 12. Section across the Vale of Wardour 11 „ 13. Quarry south of Tisbury, Wiltshire 13 „ 14. Melanopsis harpseformis, Dimk 19 „ 15. Physa Bristovii, Forbes 19 „ 16. Paludina elongata, Sow. 19 „ 17. carinifera, Sow.- 19 „ 18. Corbula alata, J. Sow. 19 „ 19. Cyrena media, J. Soiv. ' - . 19 , 20. Ostrea distorta, J. Sow. 19 „ 21. Uniosp. 19 22. vatdensis, Mant. 19 „ 23. Cypridea punctata, Forbes - 19 „ 24. ; — granulosa, Sow. 19 „ 25. Cypris purbeckensis, Forbes 19 „ 26. Archieonisjcus Brodiei ; M. Edw. - - 19 „. 27. Section at Chilmark, in the Vale of Wardour - . 21 „ 28. Section at Wockley, near Tisbury - 22 „ 29. Section in the Railway-cutting west of Dinton Station 26 „ 30. Section at Dinton - 27 „ 31. Ammonites [Hoplites] interruptus, Brug. 38 „ 32. '■ f I splendens, Sow. ■ - 39 „ 33. [Schloenbachia] rostratus, Sow. 41 „ 34. Pecten asper, Lam. - 41 „ 35. Exogyra conica, Sow. 41 „ 36. Ostrea vesiculosa, Sow. - 41 „ 37. Section of Railway-cutting at Baverstock, Wiltshire 43 „ 38. View of Quarry at Steeple Langford . 53 GEOLOGY OF THE COUNTEY AEOUND SALISBURY. CHAPTER I. INTRODUCTION. Sheet 298 of the Geological Survey Map takes in an area of 216 square miles, belonging to Wiltshire and including the southern part of Salisbury Plain, the Vale of Wardour, and part of the Avon Valley '.* At its north-east corner the Map just overpasses the Hampshire boundary ; but only takes in a quarter of a square mile belonging to that county. Salisbury and Wilton are within its limits, which extend westward to Tisbury, north- ward to Amesbury and Stonehenge, and eastward to East Grimstead. Most of the district is occupied by undulating Chalk Downs, which rise in a few places to 700 feet, and even reach 766 feet above the sea on White Sheet Hill. The Downs are deeply trenched by river valleys, all tributaries of the Avon, and one of these valleys, that of the Nadder, lays bare a few square miles of older Cretaceous and of Jurassic Rocks in the Vale of Wardour. These older strata give rise to scenery of a totally different character, with sandy heaths, clay flats, and outcrops of limestone ; making bold scarps and fiat- topped hills very unlike the rounded Chalk Downs. This difference of scenery marks off the Vale of- Wardour as something apart from the remainder of our district. Another small area of distinct character — sandy or clayey, well-wooded land — is formed by the Tertiary syncline near Alderbury, which, however, only occupies about seven square miles. This region is mainly devoted to agriculture, the Chalk Downs forming excellent pasturage for sheep, while the valleys are noted for their dairy-farming. Most of the area, even of the high and exposed Salisbury Plain, is now under the plough ; but * For " List of Books, Maps, Papers, &c, on the Geology, Mineralogy, and Palaeontology of Wiltshire " to the year 1873, by Mr. W. Whitaker, see Wilts. Archceol. Mag., vol. xiv., p. 107, 6152. B 2 THE GEOLOGY OF SALISBURY. the character of the land varies greatly, even over the same rock. Some areas of Upper Chalk, like that around Stonehenge, are dry, having only a few inches of soil ; whilst others have five or six feet of stony" loam, which makes a wet soil and supports extensive woods. The soils in the Vale of Wardour are so greatly mixed, through downwash from the scarps on each side, that in that region there is but little land the soil of which can be said to be the direct product of the rock on which it lies. The other industries connected with geology are mainly the quarrying of Purbeck and Portland stone for building and road metal, of Chalk for lime and cement, and the digging of brick- earth and sand for building-purposes. Over great part of the area the loose Chalk-flints found in the fields are used for road- making. No ores are obtained in the district, the only under- ground workings being those for the extraction of the Portland stone around Tisbury. The formations represented in Sheet 298 are as follows : — .Recent Alluvium. r Brickearth. ^ Pleistocene - gftfel. <- Clay with Flints. {Bagshot Sand. London Clay. Reading Beds. (Upper Chalk. Middle Chalk. Lower Chalk. Upper Greensand and Gault (Selbornian). Lower r Lower Greensand Cretaceous I Wealden. ' Upper Purbeck. Middle Purbeck. Upper Lower Purbeck. Jurassic j Upper Portland. Lower Portland. . Kimeridge Clay. The strata beneath the Kimeridge Clay have nowhere been reached within the area described in this Memoir. There seems reason to believe, however, that several thousand feet more of Secondary strata would have to be passed through before any Palaeozoic rock could be touched. Under these circumstances it seems useless to discuss the possibility of Coal Measures being met with. Before entering on the description of the strata above tabulated, it may be useful to say a few words on the underground structure of the district ; for in this region the appearance of the rocks at the surface is due more to underground structure than to any strongly-accentuated system of hill and valley. If a general geological map of this part of England be referred to, it will be seen that two systems of disturbance dominate the whole area. There is, in the first place, a general uptilt toward the north-west, causing a strongly-marked north-east and south-west strike of the rocks from the Wash to the Devon coast. Every stratum INTRODUCTION. 3 has been so tilted that the newer rocks occur, in general, towards the south-east. But this uplift, which cuts off the London and Hampshire Tertiary Basins, and gives a general, though slight, south-eastward cant to the strata throughout the Salisbury area, is modified by a series of sharp folds with axes nearly east and west. These east and west folds are most strongly developed in the coast region between Brighton and Weymouth ; but two of them enter the area described in this Memoir. On the east of Salisbury a synclinal trough extends from the Avon at Alderbury, through East Grimstead, to the River Test outside our district. West of Salisbury a well-marked anticline coincides with the Vale of Wardour and causes the Cretaceous rocks on either side to dip towards the north-north-east and south-south-east respectively. An older disturbance, which affects the Jurassic and Lower Cretaceous rocks, but does not affect the Upper Cretaceous, occurs in the same area ; but this disturbance, though important, cannot easily be dealt with until the various strata involved have been described. It will be again referred to. 6i.w. B lj 4_ THE GEOLOGY OF SALISBURY. CHAPTER II. KIMERIDGE CLAY. The Jurassic rocks of the Vale of Wardour appear in succes- sion from beneath a covering of newer strata. The two series dip in the same general direction, and have the same dominant strike ; but the older rocks dip at a higher angle than the newer, so that newer and newer Jurassic strata appear as the valley is followed eastward. Three miles west of Tisbury, Upper Cretace- ous strata rest immediately on the Kimeridge Clay ; at Teffont they rest on Upper Purbeck rocks; at Dmton the Wealden clays come between. Perhaps, if the valley were deeper, we might find that a few miles to the east, near Salisbury, the rest of the missing Lower Cretaceous strata are preserved. The exposure of the Portland and Purbeck rocks in the Vale of Wardour is so small and isolated that, though part of the outcrop lies without our district, it will be most convenient to complete their description in this Memoir, especially as it will only add a page or two to the bulk, and the Frome map cannot be finished for several years. The Kimeridge Clay shown in the Salisbury map crops out only in'the bottom of the valley near Tisbury ; but it is so obscured by down wash from the hills on either side that little can be said about it. There is no clear section within the area here described, though a well on the alluvium immediately north of Wallmead Farm showed black, unctuous, shaly clay. Another well, close to the stream at the Chilmark quarries, is said also to have reached very black clay beneath calcareous sandy beds (Portland) at 39 feet from the surface* It is not quite clear whether this may not have been a clay-bed in the Portland Sands ; for the foreman told me that the well was still in sand at the bottom, and that the solid clay had not been touched. At any rate, the Kimeridge Clay cannot be far below the stream-bed at this point. (See p.' 10). West of the small area here described the . outcrop of the Kimeridge Clay in the valley bottom gradually widens, until it merges into the extensive, undulating, well-wooded plain, which stretches in a wide belt from south-west to north-east almost across England. * H. B. Woodward, " The Jurassic Bocks of Britain," vol. v., p. 204, Mem Geol, Survey, 1895. PORTLAND BEDS. 5 CHAPTER III. PORTLAND BEDS* The Portland Beds comprise a very variable set of strata. In the upper part they include shelly limestones, oolite, chalky and compact limestones, with local layers and nodules of chert, and some beds of sand and calcareous sandstone. The lower beds comprise alternations of greenish-grey glauconitic sand with thin loams and clays. The thickness of the entire formation in the Vale of Wardour is about 100 feet, and it extends from near Donhead and East Knoyle on the west to Tisbury and Chicks- grove, where it sinks beneath the stream level. In the Chilmark valley, however, it again appears, and has been extensively worked. How far it extends eastward beneath the newer strata is still unknown. The Portland Beds are essentially marine accumulations. In- dications of estuarine conditions have been considered to occur in the so-called " Gyrena-beds " of the Vale of Wardour. The " Gyrena " is really a Cytherea or some allied marine genus, but Mr. Hudleston observes that the " shell, being frequently associ- ated with Cerithiwm, represents a peculiar estuarine condition, which was the precursor of the Purbecks."f Neritoma and Corbula, which also occur, may be taken to afford similar testimony. The following are the zones of the Portland Beds that are more generally adopted, together with a few of the leading fossils : — {Cytherea rugosa. SXlSSiiensi, Trigonia incurva. (Trigonia Pellati. felbruXtana. Astarte Ssemanni. Ammonites gigas has not been very definitely recorded from this country, and abroad the zone is sometimes separated and put below the zone of Gyprina Brongniarti. Still the ranges of species in different parts of the Continent seem so variable, it is impossible to mark minor zones that will hold good over any extensive region.* Organic Remains. Among the. fossils of the Portland Beds there are occasionally found remains of Saurians, including species of Gimoliosawrus, Pliosaurus, and Metriorhynchus ; and of the Chelonians, Stegockelys and Pleurostemum. The Fishes include Ischyodus, Mesodon, and Lepidotus. * By H. B. Woodward, with additions, in square brackets, by Clement Reid. t Proc. Geol. Assoc., vol. vii., p. 170 (1881). t See J. F. Blake, Quart. Journ. Geol. Soc, vol. xxxvii., p. 497 ; see also Table by Fox-Strangways, Memoir on the Jurassic Rocks of Britain, voli., p. 25. ' 6 THE GEOLOGY OK SALISBURY. Ammonites are fairly abundant, especially the large Ammo- nites giganteus, of which examples are obtained in considerable abundance at Portland. Closely related to this species is A. boloniensis. Belemnites are extremely rare. Many of the Portland Stone fossils have lost their shells, and only casts or moulds are preserved, as in the Portland " Roach." Layers of this character occur on different horizons in the Upper Portland Beds. Thus the shells of Cerithium, Neritoma, Trigonia, &c, are removed, but Pecten arid Ostrea, where present, retain their shelly matter.. The Portland Sands do not, as a rule, afford a rich field for the collector, but fossil-beds occasionally occur, from which Ammo- nites, Pecten, Mytihus, Exogyra bruntrutana, Thracia, Trigonia, &c, may be obtained. Brachiopoda and Crustacea are rare in the Portland Beds : of the latter, remains oiEryma and Glypliea have been found. No species- of Polyzoa are recorded; Echino- derms are occasionally obtained. One Coral, the Tisbury Star-coral, Isastrcea oblonga, has been found in some abundance in the Vale of Wardour ; and rarely in the Isle of Purbeck. It occurs in the Chert. Calcareous examples are not met with in England, but they occur in the Upper Oolites of Sutherlandshire. Sponge-remains (PacJias- trella) are also found at Tisbury (See p. 10.) Remains of Plarits (Araucarites) are but seldom obtained. Portland Fossils. Fit;. 2. Fig. l. Fig. l. Pecten lamellosus Sow. f . Fig. 2. Cerithium portlandicum Sou: (cast). PORTLAND. BEDS. Portland Eossils. Fig. 3. FlG . 4 _ Fig. 5. Fig. 7. Fig. 11. Fig. 6. Fig. 8. Fig. 10; Fig. 3. Cardium dissimile, Sow. § . „ 4. Trigonia gibbosa, Sow. f. „ 5. Ammonites [Perisphinctes] giganteus, Sow. rV. „ 6. Perna mytiloides, Sam. J. „ 7. Lucinaportlandica, Sow. £. Fig. 8. Cytherea rugosa, Sow. „ 9- Cyprina elongata, Blake. „ 10. Exogyra bruntrutana, Thwrm. f. „ 11. Isastrsea oblonga, Fkm. J. THE GEOLOGY OF SALISBURY. The more abundant and noteworthy fossils of the Portland Beds are as follows : — Lower Upper Beds. Beds. Ammonites [Perisphinctes] biplex 1 2 [ • — ] boloniensis - - 2 [Olcostephanus] giganteus (Fig. 5) - 2 Buccinum 1 angulatum - 2 Cerithium portlandicum (Fig. 2) - 2 Natica elegans 1 2 incisa ] 2 Neritoma sinuosa - 2 Pleurotomaria rugata - 1 2 Cardium dissimile (Fig. 3) 1 2 Cyprina elongata (Fig. 9) 1 2 implicata 1 2 Cytherea rugosa (Fig. 8) 2 Exogyra bruntrutana (Fig. 10) 1 2 Lucina portlandica (Fig. 7) 2 Ostrea expanva - - 2 solitaria 1 2 Pecten lamellosus (Fig. 1) 1 2 Perna Bouchardi 1 2 mytiloides (Fig. 6) 3 Pleuromya tellina 1 2 Voltzi 1 2 Thracia tenera 1 2 Trigonia gibbosa (Fig. 4) .1 2 incurva 1 2 -- — Pellati - 1 2 Isastrsea oblonga (Fig. 11) 2 The Vale of Wardour is one of the classic regions of the feologist. Large quarries have been opened in the Portland and 'urbeck beds, many fossils have been obtained, and the district has been described by many observers. Pyt House, a few miles west of Tisbury, was the home of Miss Etheldred Benett, one of the earliest of lady geologists, who gave especial attention to the fossils of Wiltshire, and published the first detailed account of the strata* They have subsequently been studied by Fitton,f Mr. W. H. Hudleston,+ Prof. J. F. Blake,§ and the Rev. W. R. Andrews|| (formerly of Teffont Evias). The general section of the Oolitic strata in the Vale ol Wardour is as follows : — * Ft. In. Lower ( Flaggy limestones, dirt - Purbeck ( beds, and peculiar oolitic Beds. I beds. (See page 16.) * A Catalogue of the Organic Remains of the County of Wilts, 1831 ; (privately issued). t Trans. Geol. Soc, ser. 2, vol. iv. pp. 251, 254. J Proc. Geol. Assoc., vol. vii. pp. 167-170, and Geol. Mag. 1881, p. 387. § Quart. Journ. Geol. Soc, vol. xxxvi. p. 200. || Proc. Dorset Nat. Hist. Club, vol. v. p, 66. PORTLAND BEDS. 16 24 General Section of Oolitic Strata in Vale of Wardour — contd. Ft. In. Buff sandy and oolitic lime- stones,compact limestone, and occasional chert-seams in lower part 10 to Soft white chalky limestone, with nodules and v,eins of black chert - 4 to Brown, gritty, and shelly limestone, divided in places by seam of rubbly marl 4 6 to Pale shelly and oolitic lime- stones, with rubbly shelly marl at base - Trough bed : Hard buff sandy and oolitic lime- stone, the surface covered with bivalves (Trigonia gibbosa), the bed merging into that below Glauconitic and sandy lime- stones ; divided locally into : — Green Bed - 5 Upper Portland i Upper Building Stones. Chalky Series. Kagstone. 6 Building Stones. "2 Slant Bed Pinney Bed Cleaving or ) 15 Hard Bed 1 Fretting Bed 3 4 Under Beds 3 . Lower Portland Beds. Kimeridge Clay. The finest exposures of the Portland Beds are to be seen at the Chilmark ravine, about a mile south of the village, but there arc a number of quarries near Tisbury. The Oolitic series has a general inclination towards the E.S.E., but the beds are affected by undulations, which bring the Portland Beds to the surface at Chilmark. The Upper Cretaceous rocks extend across the denuded surfaces of the older strata and form a margin to the vale both north and south. (See Fig. 12.) On the west side of the Chilmark ravine only the lower building-stones are worked, on the east side both Upper and Lower Beds are quarried, for the most part in underground workings. The overlying Purbeck Beds at the Teffont (Chil- mark) Quarry are noted on p. 21. -The lower building-stones are as follows : — Ft. In. /Chalky Series. White Bed : gritty limestone, used for hearthstone - I 6 to 4 Upper Bubbly marl (Rag) Shelly Limestones Portland ) Trough Bed : pale shelly oolitic limestone Beds, Rubbly marl, passing into Roach Green Bed : hard buff or pale greenish-grey oolite merging into bed below - 2 6 to 2 Pinney Bed : brown glauconitic and oolitic V sandy limestone in three or four layers - 12 16 24 9 18 38 105 10 THE GEOLOGY OP SALISBURY. A well at the base of the Chilmark (Teffont) Quarry was sunk to a depth of 39 feet through clays and calcareous sandy beds to very black clay (Kimeridge Clay), and water rose to within 19 feet of the surface (see p. 4). The thicknesses at this locality may be thus summarised :— Ft. In: {Upper Building Stones Chalky Series Eagstone Lower Building Stones Lower Portland Beds The Lower (or Chief) Building Stones have yielded but few fossils. Prof. Blake records Ammonites boloniensis and A. biplex. The beds contain occasional cherty masses, and a quantity of sponge-spicules may, according to Mr. Hudleston, be found in some of them. He observes that Trigonia gibbosa is found in a state of chalcedonic replacement, and states that the Pinney Bed is penetrated by a small Serpula, from the appearance of which the name is derived.* The names applied to these, building- stones vary in different parts of this district, and other names besides those mentioned have been used.-f- The Ragstone Beds are characterized by Gytlverea (" Gyrena ") rugosa, and they have been termed the "Lower Cyrena Beds." Gasteropods are fairly abundant, including the form known as Cerithium concavum, the small Natica elegans, Pseudomelania teres, Neridomus transversus, Neritoma sinuos'a and Actceonina signum.% The beds yield also Corbula, Gardium dissimile, Lucina portlandica, &c. Mr. Hudleston considered there was evidence of a break between these beds and those below. He noted at the base an irregular Trigonia-beA, with T. gibbosa and Mytilus jurensis. Trigonia Manseli also occurs in these beds. The shells in this division are well preserved. The absence of Ammonites is note- worthy,and the genera Passemblage isconsidered by Mr. Hudleston as suggestive of fiuvio-marine conditions. The Chalky Series calls to mind the similar beds at Upway. The fossils are marine and include Ammonites boloniensis, known as " Horns," Pleurotomaria rugata, Turbo apertus, Gardium dissimile, Lucina portlandica, Ostrea expansa, Pecten lamellosus, Pholadomya tumida, Pleuromya tellina, and Trigonia gibbosa._ The Upper Building Stones, termed by Mr. Hudleston the "" Upper Cyrena Beds, yield fossils for the most part in casts, and the beds have been compared to the Roach of Portland. Gerithium portland,icum is characteristic, and among other fossils * Proc. Geol. Assoc, vol. vii. pp. 171, 172. t See Section of Chieksgrove Quarry, by Miss E. Benett, Sowerby's Mineral Conohol., vol. ii. 1818, p. 58. % See Hudleston, Geol. Mag. 1881, p. 387 ; and Proc Geol. Assoc, vol. vii., pp. 167, &c. PORTLAND BEDS. 11 Ph A S3 a o o pq 5- o J. £ .a ■a 6 . ■ J? rq PP © > tT-1 T-H* £ fc 12 THE GEOLOGY OF SALISBURY. there are Neritoma sinuosa, Gytherea ( " Oyrena " ) rugosa, Trigonia gibbosa (not uncommon), Gardium dissimile, Lucira portlandica, and Pecten lamellosus. Portland Beds, with usually some thickness of Purbeck Beds on top, were worked on the north side of River Nadder by Chicks- grove Mill, and there were other quarries (with underground workings) on the south side of the river. An account of one of these was published by Miss Benett in 1818.* The locality is that of Upper Chicksgrove, and pits were opened westwards in Quarry Copse, south of the railway. A cutting on the railway west of Chicksgrove Mill, and north of Wockley, showed the following section :— Ft. In. 'Greenish sandy bed - ■ 10 Hard grey sandy limestone, weathering white : Trigonia, Ammonites - 13 Greenish and grey beds of more or less calcareous sandstone or sandy limestone 2 6 Shelly limestone : Serpula 2 6 Sandy and shelly limestone : Serpula - 2 6 Sandy marl : Ostrea, Serpula, Spine of Echinus - - 4 Grey shelly limestones 4 ('Brown and greenish-brown sand with clay seams ) and bands of indurated sand : casts of I shells here and there, thin beds of stone near ^ top - 15 to 20 Upper Portland Beds. Lower Portland Beds. The three uppermost beds merge one into the other, and are much shattered at the top in places. The fissures that sometimes traverse the rocks in this district are known as " lets."f At Wockley, south-east of Tisbury, the beds are much reduced in thickness, and their character, especially in the lower beds, is altered, for we miss the Ragstones of Chilmark. (See Fig. 28, p. 22.) The individual layers of rock also vary much in thickness. On top there is from 18 to 20 feet of Lower Purbeck Strata, beneath which we find : — \ Ft. Ft. Ik. Upper Portland Beds. /i. Bed of Roach, with lenticular mass of chert at top : Trigonia gibbosa. 3. Chalky limestones obliquely bedded, with Ammonites biplex, Plewoto- I maria rugata, Ostrea expansa, Pecten lamellosus. ' 2. Buff and greenish, glauconitic sandy limestone - 1. Compact and very shelly limestone, passing down into sandy limestone (quarried for freestone) 10 to 15 2 to 4 4 to 5 * Sowerby, Min. Con., vol. ii., 1818, p. 58. t Fitton, Trans. Geol. Soc, ser. 2, vol. iv., p. 255. J See also Fitton, Trans. Geol. Soc, ser. 2, vol. iv., p. 253 ; and Hudleston, proc. Geol. Assoc, vol. vii., p. 173. PORTLAND BEDS. 13 A quarry south of Tisbury Station afforded evidence of the variable nature of the beds. The section was as follows (see Fig. 13):- Uppe Portlai per Portland Beds. (b. Rubbly stone and marl with seam of clay 4. Shelly limestone (Roach) with \ Trigonia incur va. / 3. Impure shelly and tufaceous lime- j stone - - - -/ 2. Compact, but rotten chalky limestone, much shattered, with Gasteropods 1. Greenish glaucomtic sandy lime- stone with lenticular seams of oolitic chert : three layers seen Ft. Ft In to 4 4 to 5 3 to 4 10 to 12 Fig. 13. Quarry south of Tisbury, Wiltshire. '■'■&%!> Bedsof greenish sandstone, that become paler when dry, are dug to a depth of about 10 feet in a quarry between Tisbury and Newtown. Specimens of Trigonia are abundant on some of the blocks. Formerly much stone was obtained at Lower Lawn, and extensive old quarries are to be seen there. Looking generally at the ^ variations exhibited in the ■2 different quarries, to the attenuation and local absence of beds that may be classed with the Upper Building Stones, Mr. Hudleston remarked there was evidence of discordance between the Purbecfc and Portland Beds in the Vale of Wardour.* No doubt there are abrupt changes here and there between the formations, as there sometimes are between individual beds in the Portland series. There is, however, no discordance such as would imply upheaval and denudation of the strata. The phenomena may be attributed in part to contemporaneous erosion, in part to the attenuation and local deposition of certain sediments; while,again,the variations in the lithological characters of different layers serve to render the results of minute correlation very difficult and uncertain. . Tisbury has been long famous as the locality for the Star Coral, Isastrcea oblonga, which occurs in the Portland chert, and polished specimens of which are to be found in most collections. The exact position of the bed yielding this "Siliceous Madrepore " has been a matter of some doubt. It was described in 1729 by John Woodward as the "Starr'd Agate." He says: '■' This was found, amongst several others, lying on Floors, like the * Hudleston, Proc. Geol. Assoc., vol. vii., pp. 170, 173, 174. See also J. F. Blake, Quart. Journ. Geol. Soc, vol. xxxi., p. 191. 14 THE GEOLOGY OF SALISBURY. common black Flints, amongst Chalk; * * * Underneath these Floors of starred Flints lay Strata of Sand stone, in a Quarry in Tisbury Parish."* This position in the Chalky Series agrees with that assigned to it by the Rev. W. R. Andrews, who has found the fossil above the Ragstones at Newtown, Tisbury. Most of the specimens have, however, been obtained from ploughed fields to the north-west of Tisbury. The horizon also agrees with that noticed by Miss Benett, who states that the Coral was found above the Portland rock (i.e., building-stone), in a well sunk at Burton's Cottage, near the Inn, at Fonthill Giffard; the same authority recorded the following section of a well at Butcher's Knap(field), Tisbury : — f Ft. In. Rubble of Portland Beds 10 Siliceous Madrepore 1 Portland Beds - - 42 (Water.) [In the course of the new Geological Survey (in 1900) several specimens of this silicified coral were discovered in place in the lane which runs westward from the main road half a mile north- west of Tisbury village. They occur imbedded in chalky lime- stone at its junction with the hard cherty limestone, worked in the quarry just below. The corals are in their position of growth. — C.R.] Fitton mentions the finding of Ammonites biplex in chalcedonic flint, and states that many specimens of 'the Tisbury Coral had been obtained from " a continuous bed of flint, about 2 inches thick," exposed in one of the quarries formerly worked to the south of Fonthill Giffardj It has been found also at Chilmark. In a cutting on the road-side between Tisbury and Wardour, near Hazelton, and in other sections, Mr. Hudleston noted the following beds beneath the main building-stone : — § Ft. In. tj [ 3. Loose sands with doggers - 7 Portland ■! 2 ' greenish concretionary limestone tj„j I grit, with occasional lydite : J3eas - I originally a Trfgonia-bed - 3 Lower f Portland •! 1. Loamy sands and clays 21 Beds. { From the hard band (2) he records the following species : — Mytilus jurensis. Natica elegans. Avicula credneriana. Cardium dissimile. Exogyra bruntrutana. Pecten laruellosus. Perna Bouchardi. Trigonia gibbosa. Prof. Blake, who first noted these beds, identifies the Trigonia as T. Pellati.\\ The fauna, as remarked by Mr. Hudleston, seems * Nat. Hist. Fossils of England, Tome II., p. 77. + Cat. Org. Kem. Wilts, p. iy. ; see also Hudleston, Proc. Geol. Assoc vol vii., p. 167. % Trans. Geol. Soc, ser. 2, vol. iv., p. 255. § Proc. Geol. Assoc, vol. vii., p. 172. II Quart. Journ. Geol. Soc, vol. xxxvi., p. 202. PORTLAND BEDS. 15 very little different' from that of the building-stones : " It is what one would call an average Portland stone fauna of the large type, somewhat modified." The occurrence of the bed with lydites is interesting, as we find other such pebbly layers when we trace the beds over the exposures onwards to Buckinghamshire, and the horizon seems to be fairly constant. [These beds are probably the source from which are derived the similar pebbles found at the base of the Lower Greensand and Gault, and described in Chapters VI. and VII.] 16 THE GEOLOGY OF SALISBURY. CHAPTER IV. PURBECK BEDS.* The Purbeck Beds comprise a series of clays and shales with " Beef," marls, marly, tufaceous, and shelly limestones, and occa- sionally of granular oolitic beds, and sandy strata. In thickness the series varies from about 80 or 90 feet in Wiltshire to nearly 400 feet in Dorsetshire. The term "Beef" applied by workmen to the seams of fibrous carbonate of lime, was so given from " the resemblance of its small and parallel fibres to the fibres of animal muscle."f It often presents a cone-like structure, similar to that known as " cone-in- cone." J Pseudomorphous crystals of rock-salt were noticed by H. W Bristow in the Lower Purbeck Beds of Durlston Bay . and Lulworth Cove ; and similar pseudomorphs have been observed in the Vale of Wardour. § Gypsum sometimes occurs, and here and there we find nodules of chert. Nodules of chert occur in the Lower and Middle Purbeck Beds of the Vale of Wardour. A specimen of chert or flint from the lower part of the Purbeck Beds in Chilmark quarry, in the Vale of Wardour, was examined by Mr. W. H. Hudleston, who observed that it showed portions of marly limestone partially silicified, sealed together with purer chalcedony. The rock con- tained oolitic, granules, a fragment of shell, and valves of Cypris : some of the oolitic granules of characteristic type (were immersed in more or less pure chalcedony.|| Hence the flint resulted from the silicification of calcareous matter. Another specimen of oolitic chert from Chilmark, examined by Mr. Teall, showed the oolitic grains to be partially silicified, the inner portions of the grains being calcareous. The Purbeck Beds in most places rest comformably on the Portland Beds, and are overlaid conformably by the Wealden strata. The junction with the Wealden Beds shows a much more gradual passage than that between the Purbeck and Portland Beds, and yet on the whole, as remarked by Sedgwick, the general lithological characters of the Purbeck Beds seem to unite them more closely with the stony Portland Beds. Many authorities following Webster and Fitton, amongst whom are Godwin- Austen, Oppel, and Ramsay, grouped the Purbeck Beds * By H. B. Woodward, with additions, in square brackets, by Clement Reid. + Buckland and De la Beohe, Trans. Geol. Soo., ser. 2, vol. iv., p. 11. J See Memoir on the Lias of England and Wales, p. 308. § Andrews and Jukes-Browne, Quart. Jburn. Geol. Soc.| vol. 1., p. 52. || Proe. Geol. Assoc, vol. vii. p. 181, and Plate I., Fig. 1. PURBECK BEDS. 17 -water fa, ^ en » f° r palseontologically, by reason of their fresh- formatio U * 8 ' tbe y are more intimately connected with that and*1850 d - ForbeS ' who niade a study of the Purbeck Beds in 1849 frr>TY. f u t> n c ° m P a ny with Bristow, did not recognize any passage irom tne Portland into the Purbeck Beds in the Isle of Purbeck, ana observed that the top beds of the Portland series were marine, the lowermost Purbeck Beds purely freshwater. At the pa .™ e ™ie he concluded that the Purbeck Beds were connected with the Oolitic group rather than with the Cretaceous, and he was evidently influenced by his discovery of the Echinoderm Cv^ cidaris purb&Jiensis, which he found in a layer above the ^ e S*v Br it. Assoc, for 1870, p. 77; and A S. Woodward, Proc ZooT Soc ' fe p. 346. "' au > 6152. „ 18 THE GEOLOGY OF SALISBURY. such as occur on the American coast at present, and which may be salt or brackish, according to the extent to which the sea- waters are excluded by sand-bars from mixing with the fresh waters flowing from the land."* Indeed, Forbes, in his early account of the Purbeck Beds, indicates nine or ten alternations of freshwater, brackish water, and marine conditions in the Purbeck Beds ; and remarks that they are not marked by any -striking physical characters or mineral changes.+ Brackish water conditions were indicated by the occurrence of Gorbula, Gyrena, Cardium, Melanopsis, and Eissoa, and perhaps by the Ostrea distorta. The Purbeck Beds have yielded an exceedingly varied series of fossils. Perhaps of the highest interest are"' the Mammals, which at present have been obtained only from the base of the Middle Purbeck Beds of Durlston Bay — in a thin earthy or "Dirt" layer. -» - Among the fossils from the Purbeck Beds the Saurian remains-- are important. The Dinosaurs include Iguanodon and Nutketes; then we have the " Swanage Crocodile," Goniopholis crassidens, and the dwarf Crocodiles known as Nanwasuchus and Theriosuclms. Owen estimates the average length of a mature Theriosuchus at eighteen inches. Turtles have been obtained mostly from the quarrymen, as they occur in the stone-beds: they include Tretosterinum, Plewrostemum, concinnwm, P. Bulloohi, and -Ghelone obovata. The Fishes include Astera- canthus verrucosus, Catwus, Coccolepis, Hybodw, Lepidotus, Macrosemius, Ophiopsis, and Pleuropholis, and they are mostly found in the stone -beds worked at the quarries. Specimens occur at various horizons in the Purbeck Beds, and some of the best preserved examples have been obtained from the neighbourhood of Teffont Evias, in the Vale of Wardour. It was the intention of Edward Forbes to publish an account of the Invertebrata of the Purbeck Beds of Dorsetshire ; and he had assigned names to a number of new species of Mollusca, which he was the first to discover. J Some of these have been figured in Lowry's Chart of Characteristic British Fossils, and others in works published on the Continent. They all belong to living genera, and, taken by themselves, possess a Tertiary or even recent aspect. Eeference has already been made to the principal genera of Mollusca found in the Purbeck Beds, but it may be mentioned that Mr. Carruthers has described, under the name Teudopsis Brodiei, a cuttle-bone from these strata in Dorset. § Insects are represented very fully by remains referred to Coleoptera, Orthoptera, Diptera, Neuroptera, and Hemiptera. * Rep. Brit. Assoc, for 1872, Sections, pp. 92, 93. See also Meyer, Quart. Journ. Geol. Soc, vol. xxviii., p. 244; and Ramsay, Address to Geol. Soc, 1864, p. 32 ; and Physical Geology and Geography of Great Britain, ed. 6, 1894. t Rep. Brit. Assoc, for 1850, p. 81. t Some figures of Purbeck fossils will be found in the works of Fitton, Trans. Geol. Soc, ser. 2, vol. iv. Plates XXL and XXII. ; Mantell's Geological Excursions round the Isle of Wight, ed. 3 ; and Damon's Supp. to the Geology of Weymouth, &c, ed. 3, 1888. § Quart. Journ. Geol Soc, vol. xxvii. p. 448. Fig. 14. purbeck fossils. 19 Fig. 15. Fig. 16. Fig. 17. Fig. 18. Fig. 22. Fig. 24. Fig. 23. Fig. 20." & 21 8 OtOlO The lowest Purbeck Beds are exposed in the great quarries of the Chilmark ravine.* A pit on the north-east side showed the following beds : — Fig. 27. — Section at Chilmark, in the Vale of Wardowr. (H. B. Woodward.) Flaggy limestone and marly\ Ft. In. clay- Dirt Bed, 1 ft. to 18 ins. thick, like the Great Dirt Bed of Portland, a car- bonaceous clay with re- mains of Cycads, and with rounded lumps of lime- stone and decomposed \ chert - - - • -I White marly rock and clay of irregular thickness - Dirt Bed, marly and carbon- aceous clay with stones - Marly clay and irregular earthy limestone Tufaceous and granular oolitic stone, irregular -, Earthy tufaceous limestone with chert seams, passing down into pale fissile and earthy limestone Buff oolitic stone, forming roof-bed of mine, with marly band at base: Cerithium, Gytherea. Buff compact oolitic, and in places rather sandy lime- stones. (Upper Building Stones.) Seen to depth of 12 feet, the lowest bed containing chert Messrs. Andrews and Jukes-Browne record Mantellia (Cycade- oidea) microphylla ; and in the layer above noticed as the upper Dirt Bed, they observed an upright and rooted stump of a tree, the stem standing about 6 feet high. The Lower Purbeck Beds were observed by Fitton in some of the old quarries at Upper Chicksgrove. The details of the strata vary considerably from place to place, even in one quarry, as at Wockley. There the general section noted in 1885 was as follows : — 6 3 o Lower Purbeck Beds. 14. 13. 12. 11. 10. 9. 8. Ft. In. 1 Loamy soil 6 to Fissile limestones, some oolitic ; and marls and clays with layers of sandy limestone and sand : about 8 Hard marly limestone Banded limestones and marls 2 Dark clays 1 Sandy limestone Earthy marl with irregular (? concre- tionary) masses of stone 3 * See also J. F. Blake, Quart. Journ. Geol. Soc, vol. xxxvi. p. 200 ; and Andrews anil Jukes-Browne, Ibid, vol. 1. p. 48. 22 Tt£E GEOLOGY OV SALISBURY. Lower Purbeck Beds. Upper Portland Beds. (See p. 12.) Ft 3 In. Fig. 28. Section at WocMey, near Tisbury. H. B. Woodward. 7. Fissile limestones - 2 to 6. Dark shaly clay, much squeezed up in places. 5. Compact limestones - 2 4. Boacny bed with chert at top. 3. Chalky limestones. 2. Sandy limestone. 1. Shelly and sandy limestone. The Purbeck Beds resemble in some respects the lower beds of Lulworth Cove and Worbarrow. They undulate, and are much broken up in places. Bed No. 6, which was best shown in the northern part of the pit, may represent one of the Dirt Beds, while Bed 8 reminds one of the Soft Burr and Bacon Tier of Portland. Messrs. Andrews and Jukes-Browne* figure a curious disturb- ance in the beds, but we saw nothing so striking as they have represented (in a slightly diagrammatic manner), either in 1885 or on subsequent visits. In the Museum of Practical Geology there is a " Large Block of Limestone, showing the Junction between the Portland and Purbeck formations from Oakley [Wockley] Quarry, near Tisbury." It was thus described by H. W. Bristow : " In the quarry from which the specimen was taken, the uppermost bed of Portland Stone is harder than the chalky limestone upon which it reposes, and is crowded with marine shells common to the formation, viz., Trigonia, Cardium dissimile Ostrea, &c. Immediately above this stratum is a bed of hard, grey, bituminous limestone the upper foot of which is fissile and used for flagstones. In the specimen, as in the quarry, the exact line of junction between the shelly bed and the fissile limestone is scarcely dis- tinguishable to the eye, but when broken by a heavy blow the Portland Stone and the Pur- beck split off from each other at the junction, along a smooth and even surface. The line of demarcation between the two strata is crowded with fish."t In theirsection at Wockley Messrs. Andrews and Jukes-Browne group with the Portland Stone the hard flaggy limestone that we have included at the base of the Purbeck Beds. They state that the flaggy and shelly portions " are firmly welded together, and would yield a slab like that at the Museum of Practical Geology, in which Portland shells are visible in the lower and Cyprids in the upper part, but these Cyprids are not freshwater species, being,in fact, Candona ansata and 0. bono- niensis (which are estuarine forms ). From * Quart. Journ. Geol. Soc, vol. 1. pp. 49, 52. t Catalogue of Rock Specimens, ed. 3, p. 139. 4 ." //'/*'& "t PURBECK BEDS. 23 the flaggy portion two species of fish have been obtained (Ophiopsis oreviceps and 0. penicillatus) and also a large species of Archceoniscus." Furthermore, they obtained from the beds above, Candona ansata, Gypridea, Gypris, Gardium and Gorbula alata* To be consistent, however, we must continue to regard the old. plane of division as the best, and going again to the district with Mr. Strahan no difficulty was found in determining this junction in the quarries near Tisbury and Chilmark. The evidence of the fossils shows that the change of conditions was not so marked as in other localities where freshwater beds overlie those of a marine character. Here we have estuarine beds overlying marine beds, while in other places in the Vale of Wardour the " Cyrena-beds " of the Upper Portland Beds have been regarded as of a semi- estuarine character. (See p. 5.) An interesting section to the south-east of Eidge has been noted by Messrs. Andrews and Jukes-Browne as follows : — -J- Ft. In. Lower Purbeck Beds. Dark brown soil Weathered marlstone or " lias " Buff-coloured marl, with seams of grey clay Soft fine-grained, marly oolite, a mixture of oolitic particles with triturated shells, cyprids, &c. ; with thin layers of harder compact marl- stone in the lower part Soft yellowish calcareous oolitic sand Very hard limestone, consisting of shelly layers alternating with seams of com- pact marlstone Soft marl with yellowish oolitic stone Hard grey shelly limestone Oolitic stone with layers of marl Soft calcareous stone passing down into hard limestone with pseudomorphous crystals of rock-salt : Gorbula alata, Perna, Gardium, Nueulana,Serpula,kc. Grey laminated marl - Buff marlstone 6 2 3 9 10 3 2 2 4 3 3 3 3 1 3 22. 4 To the west of Bidge the basement-bed exposed at the outcrop is a tufaceous limestone with large masses of wood. Many blocks of this limestone are pldughed up ; but no section is now visible in it. To the south-west of Teffont Evias Church there is a long excavation in the Purbeck stone-beds which present a general resemblance to Lower Lias limestones, and many beds are known * Quart. Journ. Geol. Soc, vol. 1. p. 51. See also Fitton, Trans. Geol. Soc, ser. 2, vol. iv. p. 253. t Quart. Journ. Geol. Soc, vol. 1, p. 52. 24 T&E GEOLOGY OF' SALISBURY. to the quarrymen as " Lias." The best section is near the Lime- kiln at the northern end of the workings; this was noted as follows : — Ft. In. Middle Purbeck Beds. Lower Purbeck Beds. Brashy soil, brown sandy loam. _ /Cherty layer with many bivalves [Cyclas]. Cindek Bed: hard greyish brown lime- stone, much broken up ; Ostrea distorta, [Trigonia allied to gibbosa, and spine of Hernicidaris] Clay and rubble - - . ,- Hard grey limestone with dendritic markings - Grey shelly limestones, splitting up ir- regularly ; the bottom bed called White Bed (6 ins. to 1 ft.) [Chelonian bones, Hybodus, Cyprides] Shaly limestone, with curious concre- tionary projections from base of White Bed, which disturb this N stratum [Modiola] 'Pale grey rubbly marls - White Limestones [Lias No. 1] Sandy marl and clay [MeSodon, Estheria, and Cyprides] - Sandy shell-limestone Blue Kock [or Flagstone] ; blue-hearted stone, weathering buff, with brown ferru- . ginous base called Scale, showing tridactyl markings on under surface. Cyrena [Fish-remains] Clays and Shales with Cypridea granu- losa, [Cypris purbeckmsis] Hard white marl -"1 [ Soft marl - - \ [Lias No. 2] \ Hard marly limestone-J (. .Soft white marl - - - - - Hard white marly limestone [Lias No. 3] 6 4 6 3 3 3 3 The above section has been described in more detail by Messrs. Andrews and Jukes-Browne, and we have added in square brackets some of the fossils recorded by them. They had an excavation made below the floor of the quarry, and their observations showed that the lowest bed of " Lias " (No. 3) above noted, was 3ft. 6in. thick, and beneath were nearly 8 feet of marls and marly lime- stones. From the Lower Purbeck Beds, and especially from the bands of " Lias," Mr. Andrews has obtained many fish-remains, includ- ing Gatv/rus, Goccolepis, Leptolepis, and Pleuropholis. Many of these are very beautifully preserved, but all are diminutive when compared with the Purbeck fishes of Dorsetshire.* The Purbeck stone-beds, comparable with those of Teffont Evias, have also been quarried for road-metal and building-stone on the south of Lower Chicksgrove. There is a band of hard * Quart. Journ. Geol. Soc, vol. 1. p. 53 ; and A. Smith Woodward, Geol. Mag., 1895, p. 145. grey limestone, like the Swanage stone, .and compact smooth- 5 ;ramed limestone termed " Lias " (2 feet thick). These beds over- ie shelly limestones and marls, with decomposed shelly layers and "beef"; with Paludina and. Modiola. The Cinder Bed, as noticed by Messrs. Andrews and Jukes-Browne, occurs above these beds, and is surmounted by a marly oolitic limestone, .and by clays with " beef," &c* Higher up occurs the Isopod Limestone discovered by the Rev. P. B. Brodie,f a band containing Archceoniscus Brodiei in multi- tudes here and there, although the stone may in places be split up without any specimens being observed. This fossil occurs also at other horizons, but the particular bed above-mentioned is a smooth-grained limestone that may be readily identified in the neighbourhood of Dinton. About a mile west of Dinton Station, and extending north- westwards along the scarp into Teffont Park, there are traces of old stone-pits. Some of these must be at or near the spot where Fitton noted his section at Dallard's Farm. This showed about 12 feet of slaty stone and clay with Ostrea distorta, Modiola, Corbula alata, and Cyprides. Others are nearer the present line of railway, and are those described by the Rev. P. B. Brodie and the Rev. 0. Fisher. Fitton mentions that on Ladydown, quarries have long been worked for the sake of tilestone — a fissile stone, yielding Cyrena and remains of Fishes.^ One of these quarries is still open. Somewhat higher beds probably were opened up at Dashlet, on the south side of the Nadder, to the north of Fovant, for there Fitton noted oolitic particles in the top layer of stone, and found Ostrea distorta, Fish-remains, &c, in a compact, limestone at the base of the quarry. In these quarries no doubt the stone was obtained below the Cinder Bed. The quarry at Dashlet is now overgrown. [A good exposure will be found in the stream-bank at the end of the wood, south-east of Teffont Mill. It shows : — Ft. In. Alternations of white clay and white earthy limestone 4 Harder light-coloured limestone with carbonaceous matter and fish-scales - 10 . White marl - - - 4 ^ Oolitic limestone (at water level) This section is difficult of access when the mill is working, and as no characteristic fossils could be fouud, there is some doubt as to the exact horizon.] Clear sections of the strata from the Cinder Bed up to the junction with the Wealden Beds have been exposed in the two railway-cuttings to the west of Dinton Station. The second cutting west was described in detail in 1881 by the Rev. W. R. Andrews, who obtained from the Cinder Bed the new species Trigonia densmoda. * Quart. Journ. Geol. Soc, vol. 1. p. 54. t Proc. Geol. Soc, vol. iii. pp. 134, 780 ; History of Fossil Insects, pp. 3, 18, 19 j and Quart. Journ. Geol. Soc, vol. x. p. 474. t Trans. Geol. Soc, ser. 2, vol. iv. pp. 249-251 ; see also Brodie, Proc. Geol. Soc, vol. iii. p. 780. 26 THE GEOLOGY OE SALISBURY. a S3 A O O W 5Q T3 H & g lO o JO i-H •=» -ta c» 1= O <£> r^ © oj CO 03 O § §> CO ft -to s o S* 8 § i*^i •■s> 8 ft* oi (5 I— I ft ••.*§ a. © o Id ^ B Mr. Andrews, then took Bed 19 as the top of the Middle Purbeck Beds, believing that they were overlaid unconformably by his " Wealden " Beds 20* The clear connection with the overlying beds was not manifest, and when examining the sections in 1885 I (H. B. W.), noted the various strata that occurred above the Isopod Limestone onwards to the white and coloured clays on top of the series near Dinton Station. These white clays I took to be Wealden, and thought they were the beds so described by Mr. Andrews. The bed of hard eroded marl (19) described by him, is identical in character with Bed 27, and this caused my misinterpretation of his* section. In the meanwhile Messrs. Andrews and Jukes-Browne have given further particulars of the strata, and have included with the Upper Pur- beck Beds, strata that I regard as Wealden. f In the spring of 1894 Mr. Strahan and I examined the area, and were fortunate in finding a fresh cutting near Dinton Station, the railway having been widened for the extension of the siding. We were thus enabled to measure all the strata from the base of the white clays, which we regard as Wealden down to the- blue clay taken by Messrs. Andrews and Jukes-Browne as the base of .the Upper Purbeck. Examining also the second cutting, where the Isopod Limestone is well shown, we were led to believe that that band would be met with a foot or two below the lowest bed exposed in the first cutting. Getting assist- ance in digging a hole, we were successful in finding this well- marked band of limestone No. 13, and thereby confirmed our previous inference that there was no dis- cordance and no evidence of fault- ing between the two cuttings. * Pvoc. Dorset Nat. Hist. Club, vol. v., p. 68 ; Quart. Joum. Geol. Soc, vol. xxxvii., p. 251. t Quart. Journ. Geol. Soc, vol. 1., p. 55 ; an/1 TT Tt W Thill r. 71 PURBECK BEDS. 21 The following is the section exposed in the railway-cuttings west of Dinton railway-station (see also Fig. 29, p. 26) : — Fm. 30. Section at Dinton. (H. B. WOODWAKD.) ■<;> /.: Kh B I. V- Ft. In. (Zi. ^regular gravel passing down into whitish stony clay - 5 33. White, grey, and mottled clay, pass- ing down into white and ocbreous clay with seam of greenish sand - 3 32. Laminated yellow ocbreous clay and sandy seams - - 2 3 31. Brown, black, and wbite sand, and thin layer of laminated clay 6 , 30. White marl parsing down into clay : . - with Cyprides - - - 1 4 29. Shelly calcareous grit - ljtofl 3 28. Gritty marl - -.03 27. White marl with black (carbonace- ous ?) matter on top - 4 to 8 26. Blue clay .... - 5 25. Bluish-grey calcareous sandstone - 3 24. Marls and clays, with thin bands of " beef," and thin impersistent layers of sandstone - 1 9 to 2 6 23. White shell-marl, with thicker bands of " beef " - 3 22. Dark blue clays, with shell-marl, " beef," and ferruginous matter 2 6 to 3 3 21. Blue-hearted shelly and sandy lime- stone with greenish earth in places, lignite, Unio, Paludinu. Brown calcareous sandstone. The whole passing into sand with ferruginous layers - - 2 8 20. Yellowishsands and laminated sands and clays, passing downwards and laterally into stiff blue clay 4 0to6 19. Hard-jointed white marl, the surface eroded and the hollows filled with clay (like Bed 27) - ljtol 3 18. Thin laminated marl, with layers of clay and sand, shelly bands and "beef" - - 16 17. Calcareous sandstone passing into sand - 1 to 1 16 Clay with shelly bands . - 15. Brown sandy rock with Cyrena 14. Shell-marl with greenish tinges 13. Smooth-grained grey limestone with ArchcBoniscus 12. Sandy shell-marl 11. Grey marly and ferruginous lime- stones - 10. White limestones 9. Shelly and sandy limestones. Fish- remains 8. Shell-marl with " beef " 7. Cinder Bed : earthy limestone with Ostrea dislorta 6. Marly and sandy layer with " beef " 5. Grey sandy and shelly limestone v with marly seam / 4. White limestone J 3. White limestone J 2. Marly bed ' 1. Brown sandy limestone 1 6 1 3 6 1 3 3 9 1 3 5 5 1 3 5 1 8 6 7 1 28 THE GEOLOGY OF SALISBUBY. Still lower beds were noted as follows, in the adjacent quarries, by the Kev. 0. Fisher in 1853 : — * Ft. In. Ribbon clays and sands, with com- pressed shells - 10 Hard crystalline limestone, with com- minuted shells, Gypris and Cyrena 1 6 Brown sand, full of crushed bivalves and Serpulae - - 9 Blue and grey laminated clay with limestone nodules, thin " beef," and crushed bivalves - - 10 Hard grey marly limestone 3 6 Dirt-bed - - 3 Laminated clay and soft and hard marls - - - 16 Hard marl with conchoidal fracture 8 These lower beds represent the " Lias " beds, &c, of Teffont ; from the Middle Purbeck the following fossils were obtained : — Lower Purbeck Beds. Lepidotus. Avicula dorsetensis. Cardium. Corbula. Cyrena 1 gibbosa media. Modiola. Mytilus. The " Upper Marls " noted by Messrs. Andrews and Jukes- Browne were proved in the well at the cottages north of Dinton Station. This well was probably carried down through Wealden and Purbeck clays to the fossiliferous bed No. 21. The thin bands of calcareous sandstone above are, like the thicker beds, readily decomposed, and their presence would not have attracted the notice of the well- sinker. The water would have been obtained in the sandy beds on this horizon and below. Indeed, the same beds yielded water in a shallow well sunk by the old railway-siding, and the supply failed when the siding was extended. In the material thrown out from this well Mr. Andrews obtained some Fish-scales, also the following fossils : — Paludina carinifera. Unio. Cypridea punctata. Cypridea (cf.) valdensis. Cyprione.Bristovii. . Darwinula leguminella. The evidence clearly establishes the contention of Messrs. Andrews and Jukes-Browne that the Upper Purbeck Beds are represented, though I believe theft " Upper Marls " are for the most part Wealden. In his original notes on the Vale of Wardour, the Kev. P. B. Brodie appears to have observed strata about" as high as No. 23 in the Dinton section. [Since the above account was. written the cutting has again been overgown; though a small quarry by the side of the rail still shows the beds up to No. 20.] The hard marl (No. 19) and also the similar bed (No. 27) show evidence of local dissolution. The former layer, which sometimes is 15 inches thick, has almost disappeared in places, being reduced to 1J inches. * Quart. Journ. Geol. Spo., vol. x, p. 476; see also Andrews, Ibid., vol. xxxviii, p. 251; Andrews and Jukes-Browne, Ibid., vol. 1, p. 55; and Geol. Mag., im, P- 292. PURBECK BEDS. 29 [The mapping of the Vale of Wardour on the six-inch scale in 1900 strongly supported the view taken in 1895 by Mr. Woodward as to the relation of the Purbeck Beds to the strata above, The thin marls and sands which form the Upper Purbeck were found to be continuous and to lie conformably underneath the Wealden strata. They were traced westward for over two miles to Chicksgrove, where they are overlapped, and lost just beyond the point where the Wealden sands disappear. Three outliers of Upper Purbeck age were also discovered; but there is no section beyond that seen in the railway-cutting at Dinton. The junction of the loamy Upper Purbeck with the Middle Purbeck limestones which lie below is commonly marked by a series of small swallow-holes. These are formed by the rainwater, which runs over and down the loamy surface till it reaches a porous rock into which it can sink, at the same time dissolving this rock if, as in this case, it happens to be soluble. Upwards, the Upper Purbeck strata seem every- where to pass imperceptibly into the Wealden beds above, the only noticeable difference being that the Purbeck consist of decalcified marl and sand, and the Wealden of clay and sand which do not appear ever to have contained much lime. Probably both these deposits would appear very different if we could see sections which have not been subjected to the action of percolating water. The soil of the Upper Purbeck outliers is a brown sandy marl, unlike the retentive limestone-soil of the Middle and Lower Purbeck ; but the main outcrop is so domi- nated by higher slopes of Cretaceous rock, that the character of the soil is not a satisfactory guide. c.B.] 30 THE GEOLOGY OF SALISBURY, CHAPTER V. WEALDEN. The Wealden strata, as shown in Figs. 29 and 30, rest con- formably and seem to pass imperceptibly into the Upper Purbeck rocks seen in the cutting at Dinton station. Their outcrop extends for about three miles to the west to Sutton Row, on the south side of the valley, but only to Teffont on the north. The strike and dip coincide with those of the Purbeck strata; but only the strike corresponds with that of the Upper Cretaceous escarpment further west. The upward tilting towards the north- west, which affects all the Secondary rocks, had already begun in Lower Cretaceous times; but it seems to have continued to a much later period, probably as late as Miocene. Thus the older rocks have the higher dip, and various strata of Secondary and Tertiary date tend towards the west to rest on the upturned edges of older rocks. In Dinton railway-cutting only some 10 feet of the lower part of the Wealden Beds can be examined, and the exact age of these deposits is, perhaps, not quite satisfactorily made out. At the cottages 300 yards north-east of this section, however, a well was sunk in 1884, and this showed, according to Messrs. Andrews and Jukes-Browne* : — Ft. Yellow clay 3 or 4 Light-grey silty marl - 11 or 12 Stiff grey clay - 5 or 6 Very stiff grey and brown clays - about 20 Hard gritty stone a few inches This well, according to Mr. Woodward, penetrates both Wealden and Purbeck strata, the lower part being undoubtedly in Upper Purbeck, the upper part probably Wealden. The thickness of the Wealden strata at Dinton cannot be much over 30 feet ; but on the south side of the river, near Sutton Mandeville, it may be somewhat greater. The only . sections besides those already described will be found at Panthurst, where a deep cutting shows 10 feet of blue-black sand, the road above showing blue clay and sand. Near Sutton Mandeville Mill there are also shallow exposures of ferruginous sand and yellow sandstone. Fragments of the peculiar wood known as Endogenites erosa have been found at several points in the Vale of Wardour ; but this is the only characteristic Wealden fossil yet recorded. It is too doubtful a form to be of much value for correlation, though its presence supports the view that the strata containing it truly belong to the Wealden period, and are not, as supposed by Messrs. Jukes-Browne and Andrews, of Purbeck age. * Quart. Journ. Geol. Soc, vol. 1. p. 61. (1394) ; and " The Lower Cretaceous Series of the Vale of Wardour," Geol. Mag. dec. III., vol. vii. p. 292 (1891). LOWER GREENSAND. 31 CHAPTER VI. LOWER GREENSAND. The interpretation of the Lower Cretaceous deposits in the Vale of Wardour has led to some debate; but the detailed mapping has now shown clearly that Fitton in 1827 had under- stood the true structure.* Fitton recognised that between the Wealden Beds and the Gault there occurs a thin deposit of greenish sand, very similar in character to the Upper' Greensand above the Gault, and that this deposit represents the Lower Greensand of other districts. The Lower Greensand, however, is not shown on the old map of the Geological Survey, the sand described by Fitton being considered, apparently, too thin to be mapped separately. The Lower Greensand of the Vale of Wardour consists .usually of 15 or 20 feet of glauconitic sand with rare masses of cherty sand- s'tone or chert. The only fossils I have noticed in it consist of sponge-spicules and of rare moulds of Pecten {Neithea) quinque- costatus and P. orbicularis ; both species being common to the Upper and Lower Greensand. These fossils were found in loose blocks of chert picked up in a ploughed field, and this chert is so like one variety found in the Upper Greensand that it is impos- sible to be quite certain that any particular specimen may not have been washed down from the hills above. Messrs. Jukes-Browne and Andrews, however, record the more characteristic Exogyra sinuata from a well at Dinton.f Exposures are so rare in the Lower Greensand that it will be convenient to follow the outcrop westward, first on the north side and then on the south side of the valley. At Dinton a well sunk in 1890 gave Messrs. Jukes- Browne and Andrews the following section : — Ft. ( Yellow, brown, and blue clay (with fossils) - 214 Gault { Sandy rock with a layer of small pebbles at the) , . , ( base (fossils) ... | 14 4 Vectian /"Brown, grey, and yellow sands, with lumps andl „„, (Lower J layers of ferruginous sandstone {Exogyra smuatci)) * Green- | Light grey sandy clay, becoming darker andl _ sand) V passing down into stiff black clay - J They remark that " in this well the base of the group is evidently not reached, but most fortunately it is completed by a brook section at Teffont, which begins in a black clay exactly like that found at the bottom of the well. This black clay is about six feet thick, and passes down into a nearly black sand, which has a green streak when cut, and consists mainly of dark-green grains of glauconite. * Observations on some of the strata between the Chalk and the Oxford Oolite, in the aouth-east of England. Trans. Geol. Soc. ser. II., vol. iv. p. 248 (18361. Geol. Mag. 1891, p. 293. 32 THE GEOLOGY OF SALISBURY. " Underneath this sand are mottled clays, which were recognised by Mr. Whi taker as similar to the 'catsbrain' clays of the Weald — their tints are yellow and white, mottled here and there with a rich claret-coloured stain, which imparts a special character to the clay. Below are yellow loamy clays. We consider these to be of Wealden age, and the dark sand to be the base of the Vectian ; but as the section is not clear, and this sand has not yet been found elsewhere, we cannot say whether the sand is conformable to the clays or not." I cannot help feeling some doubt as to this correlation of the clays at Dinton and Teffont, and should be inclined to refer only the 26£ feet of sandy beds to the Lower Greensand. The Gault in the above well will be more fully described in the next chapter. It may be noted, however, that its fossils belong to a higher zone than that of Ammonites [Acanthoceras] mammillatus. The Greensand first rises above the marsh-level near Dinton Mill as a coarse-grained glauconitic sand with concretionary masses of cherty sandstone, the whole deposit being apparently about 20 feet thick. Material of this sort was formerly dug over a piece of rough ground half a mile west of the Mill ; but the section is now overgrown. To the south of Dinton Park and Teffont Magna Mr. Jukes- Browne has been able to follow the outcrop as a narrow-belt of sandy land, though no section is visible. Immediately east of Teffont the Lower Greensand overlaps the Wealden Beds and rests on Upper Purbeck. Three- quarters of a mile farther west it rests on Middle Purbeck limestone, which has been dug close to the sand. At Ridge an uprooted tree, growing apparently just at the junction, brought up hard shelly limestone with oolitic grains, belonging to the' Lower Purbeck. "- Some overgrown pits immediately south of Ridge Pottery are perhaps referred to by Fitton, who does not appear himself to have seen this part of the section which he describes, though he saw the pit in the Gault above and the quarry in the Purbeck limestone below. More probably he obtained the thickness and character of the Lower Greensand from the well which is noted in his section as occurring at the Tile-pits. His section gives : — Ft. Gault - ; - - - 75 Sand ; (perhaps the representative of the Lower green-sand) \ said to be like that of the hill-top. Masses of a calcareous } 15 conglomerate in the upper part - ) Purbeck stone. I have not seen any calcareous conglomerate such as Fitton describes ; but he probably refers to the thin pebble-bed which marks the base of the Gault wherever sections are visible, though it is not now exposed at Ridge. Towards Fonthill the Lower Greensand becomes thinner and thinner, the last point to which it has clearly been traced in that direction being in the neighbourhood of Fonthill Abbey. In this area it is usually so dominated by higher slopes of Upper Greensand that it is difficult to recognise ; but in some fields west of the Rectory it runs ou as a spur, Capped only by Gault. LOWER GREENSAND. 33 Here I saw traces of disturbed cherty sand, resting on Portland Stone, and found also a specimen of Pecten [Neithea] quin- quecostatus in chert. The whole deposit does not appear to exceed five feet in thickness ; though the tendency of the soft Gault to slip and flow down slopes no steeper than this, makes measurement impossible. The same cause prevents the tracing of the Lower Greensand any farther towards the west ; but I think the deposit must be actually overlapped and cut out by the Gault close to Fonthill. The south side of the Vale of Wardour shows still clearer evidence of the presence of the Lower Greensand, and we will now follow the outcrop from Dinton south-westward. Half a mile south-west of Dinton Mill blocks of coarse-grained glauconitic cherty sandstone were noticed in Compton Wood, a few feet below the base of the Gault. These correspond closely with the material from the opposite side of the valley, and appear to be almost in place, though the soil is full of a slightly different chert derived from the Upper Greensand slope above. Pieces of this glauconitic cherty sandstone are traceable here and there as far as the road to Catherine Ford, where is the exposure noted by Fitton ; we can still see in that road traces of greenish sand between the Gault and the Wealden. Similar sand and cherty sandstone, with exceptionally large grains of glauconite, have been mapped by^ Mr. Jukes-Browne around Fovant, where it makes a somewhat wider spread, and at Sutton Mandeville. In them, at Panthurst, Fitton discovered a Pecten and the stem of a Siphonia ; no section is now to be found, but on the outcrop there is a shallow overgrown pit, which was perhaps open in Fitton's day. West of Sutton Row the Lower Greensand overlaps the Wealden Beds, and a small pit in coarse sand will be found immediately east of Haredene Wood. At the north-east corner of this wood some of the basement-bed, which here rests on Middle Purbeck limestone, is let down into a swallow-hole, in the sides of which three feet of coarse-grained greenish sand can be seen. North and east of Castle Ditches the Lower Greensand rests on Middle Purbeck, and there is some indication of a thin pebble-bed at the junction. The occurrence of gentler slopes and wider outcrops, and the greater distance of the Upper Greensand escarpment, make the exposures south of Tisbury more satisfactory than any we have yet dealt with; for though sections are scarce, abundance of Lower Greensand material without much admixture of rock from the slopes above can be found. If the road from Tisbury to Ansty and Swallowcliffe past Wallmead is followed, it will be found to cross two spurs of Lower Greensand, one at Totterdale Cottage, the other nearer Ansty. Sections are not good, but the use of the spud and an examination of the ploughed fields shows that the Cretaceous rocks here rest on the lowest Purbeck Beds, that there must be a thin seam of quartz and lydite pebbles at the base of the Lower Greensand, and that the strata above are ferruginous or glauconitic coarse sands and cherty sandstones 6152 1) 34 THE GEOLOGY OF SALISBURY. apparently with some intercalated seams of loam. Above these comes another thin pebble-bed in brown loam, forming the base of the Gault. In the ploughed fields I found several pieces of cherty sandstone with Peeten quinquecostatus and P. orbicularis ; but was quite unable to find any characteristic fossils, though a large amount of material was broken up and examined. About a quarter of a mile south-east of Tottertfale farm, a small section of the upper beds can be seen, brown sandy loam with numerous scattered pebbles (the base of the Gault) overlying ten feet of glauconitic sand. This section, unfortunately, does not show any of the harder fossiliferous rock, which seems to occur principally as irregular scattered nodules towards the base of the deposit. The total thickness of the Lower Greensand around Totterdale appears to be nearly 30 feet. To the west of this farm the outcrop is easily traced as a belt of sandy land, with loose masses of ferruginous sandstone ; but no other section is visible within the area described in this Memoir. Outside our limits a sand- pit in Wardour Park shows : — Feet {&2 ay - Lower Greensand. Coarse gritty sand 10 The strata in this pit shows a dip slightly to the south of east. There still remains for discussion the question of the probable age of the Lower Greensand of the Vale of Wardour, for its extreme thinness, the occurrence of a pebble-bed and uncon- formity at its base, and of a pebble-bed and overlap of the Gault above, do not favour the idea that we are dealing with an atten- uated representative of the whole of the Lower Greensand. It seems far more probable that this thin coarse-grained deposit represents part only of the Lower Greensand of other districts ; but what part the evidence found in the Vale of Wardour is insufficient yet to show. Though in the Vale of Wardour itself it is difficult to find conclusive evidence to settle this point, there is a pit near Okeford Fitzpaine, about 12 miles to the south-west, which throws much light on the subject. The section and fossils of the lower part were thus described in 1896 by Mr. E. B. Newton* : — Feet. Dark-grey coloured, micaceous, and sandy clay\ Hoplites with phosphatic nodules ; fossiliferous in the / 15 lower 4 feet J Zone. Brown sandy rock, with fossils in the upper! part. I 4 Acanthoceras [ Argillaceous sandy beds micaceous, and , of a ^ mammillatvm b o r0Wn - «!?■ or yellowish colour ;_ for ruginous { 7one I a " ooiltlc > siliceous pebbles interspersed ; f ° I fossiliferous. ) Aptian ? Pure sand. 3 Kimeridgian. Stiff blue clay. 8 or 10 Corallian 1 Sandy rock. Geol. Mag. 1896, p. 19S. LOWER GREENSAND. 35 From the Ammonites [Acanthoceras] mammillatus Zone he records the following fossils : — Acanthoceras mammillatum Cuculliea carinata Hoplites Benettianus Ostrea Leymeriei Pleuromya plicata Exogyra sinuata In the Ammonites [Hoplites] interruptus Zone were found amongst others the following : — Hoplites interruptus Mytilus subsimplex splendens Nucuia pectinata Nautilus clementinus Ostrea canaliculata Aporrhais carinata Thracia simplex Avellana inflata Trigonia alseformis Solarium" ornatum Trigonia archiaciana Cucullsea carinata Fittoai In this section a few feet of sandy beds 4ie between the clayey Gault and the Jurassic rocks, exactly as the sandy beds occur in the Vale of Wardour ; but in the Okeford section both deposits contain characteristic zonal fossils, and we can prove the occurrence of the zone of Ammonites mammillatus below that of Ammonites interruptus. The lowest fauna discovered in the Din ton well comes, however, not from the sandy beds described in this Memoir and mapped as Lower Geeensand, but from what I take to be the pebbly and sandy basement-bed of the Gault above ; and this basement-bed yields the fauna of the Ammonites interruptus zone (see p. 38). As to this, Mr. Jukes-Browne remarks tbat, " It will be noticed that the basement-beds are here 8 feet 8 inches thick, and it might have been expected that they would yield the fauna of the zone of Ammonites mammillatus, but this does not seem to be the case." * I think, however, that the true zone of Ammonites mammillatus is probably represented by the 26 feet of sandstone below, not by the pebbly beds. This sandstone at present has only yielded Exogyra sinuata ; but further search should produce definite evidence. As regards the classification of these strata, Mr. Jukes-Browne remarks that, " It has been customary in England to regard the Gault as commencing with clayey beds containing Ammonites interruptus, and to refer all beds below this horizon to the Lower Greensand. In France, however, the sands containing Ammo- nites mammillatus which underlie the clays with A. inter- ruptus have always been included in the Gault "or Albian of d'Orbigny." f In the.Vale of Wardour the sands referred in this Memoir to the zone of A. mammillatus are certainly more closely related stratigraphically to the Gault above than to anything below ; but as they can be mapped separately and have a markedly different lithological character they have been coloured as Lower Greensand on the map, and are still bracketed as Lower Cretaceous. At the same time they are placed in the Index to the Map at the base of the Gault, with a' marked break between them and the Wealden beds. An additional reason for * " Cretaceous Rooks of Britain," vol. i, p. 228, Mem. Geol. Survey (1900). Ibid, p. 43. 6152 D 2 36 THE GEOLOGY OF SALISBURY. this treatment is found in the unfortunate circumstance that on the Continent the Gault is nearly always classed as Lower Cre- taceous, while we class it as Upper Cretaceous. If we transfer the zone of A. mamtrdllatus from the lower Greensand to the Gault, we make this discordance greater instead of less. At present British geologists do not seem disposed to adopt the continental division between the Upper and Lower Cretaceous rocks, which is certainly not a convenient one for Britain. GAULT AND UPPER GREENSAND. 37 CHAPTER VII. GAULT AND UPPER GREENSAND (SELBORNIAN).* The Selbornian Group consists of clays and marls which are usually known as Qault, and of sands and sandstones which have been called Upper Greensand ; but it must be remembered that though both exist in Wiltshire, the Gault clays of this county represent the Lower Gault of Folkestone only, the Upper Gault (which comprises two-thirds of the formation at Folkestone) being here represented by' the so-called Upper Greensand. The following is the succession of beds which make up the Selbornian in the Vale of Wardour : — Zone of Pecten asper. Green sand or sandstone Sands with layers of cherts Glauconitic sandstone r/ n „* i , (Greenish grey sands - Zone of Am- Y buff-coloured sands momtes rostratus.}^^ malmstone Zone of f Sandy ^micaceous clay Am. mterruMtiis. i Grey and brown clays (Gault.) I Ironstone and pebble bed GAULT. Feet about 10 „ 25 „ 15 „ 40 » so „ 20 f „ 100 3 to 8 About 265 The Gault of the Vale of Wardour is a bluish marly clay or loam, tending to become sandy above and below, and having a thickness of from 80 to 90 feet. Where sections are visible there is a sharp line, marked by a few small pebbles, at its junction with the sands below, but upwards it passes gradually into the Upper Greensand. Indeed, the relation of the Gault to the Upper Greensand is so intimate, that in his " Upper Cretaceous Rocks of Britain," Mr. Jukes-Browne has introduced the name "Selbornian" for the combined formations. The two make one palseontological whole, and are merely different lithological fades of one formation. The equivalents of the Upper Gault clay tend to become so sandy towards the west as to be scarcely distinguishable Hthologically from the Upper Greensand. In this district the clay represents the Lower Gault only. It passes up into a kind of impure malmstone, or fine micaceous sandstone containing a variable quantity of colloid silica, and this in turn passes up into soft sands. Our knowledge of the Gault within the area described in this Memoir is mainly derived from two sections, a brickyard and well at Ridge, and a well sunk at Dinton, north-east of the * Mainly from Jukes-Browne's " Cretaceous Rocks of Britain," vol. i. , chapter xvi. {Memoirs Geol. Swvey), 1900. 38 THE GEOLOGY OP SALISBURY. church, in 1890. The Dinton well has already been referred to ; the section given by Mr. Jukes-Browne is as follows :— Gault clays Surface soil C Yellow and grey clays Hard ferruginous stone ; Brown clays with a layer of brown stone I Dark grey clay with selenite, some fossils and a [ few small phosphate nodules (Hard grey ferruginous sandy rock, fossils Reddish-brown sandstone with scattered pebbles, fossils and fragments of wood Layer of small pebbles - Lower /Brown and grey sands and stone beds GreensandtGrey^and black clays Ft.- In. 1 6 5 8 15 5 5 8 2 6 6 26 8 • 7 69 6 The following fossils were obtained from the brown sandstone by the Rev. W. R. Andrews and identified by Messrs. Sharman and Jukes-Browne : — Deshayesi or Modiola sp. Mytilus sp. Ostrea vesicularis. Pecten orbicularis. Pinna sp. (several). Pleuromya mandibula. Terebratula biplicata. Holaster lsevis. Ammonites sp. denarius). Natica sp. (? Genti) Area (Cucullsea) carinata. Cytherea sp. (? plana, young). Inoceramus concentricus. „ sp. (large). Lima sp. From the overlying hard grey rock were obtained : — Ammonites [Hoplites] sp. Area Raulini ? Turbo sp. (not munitus). Cardium raulinianum ? Inoceramus sp. (large). svA-hillanwrn). Cucullaea glabra. Pleuromya plicata ? „ sp. Gyprina angulata. In the clay above Mr. Andrews found the following : — Am. interruptus (Fig. 31). Pecten orbicularis. Trigonia Fittoni. Inoceramus sp. Pleuromya mandibula. Pinna sp. (not Fig. 31. Ammonites [Hoplites] interruptus, Brug. GAULT AND UPPER GREENSAND. 39 Fig. 32. Ammonites [Hoplites] splendens, Sow. The only excavation in the Gault along the north side of the Vale is that of a brickyard at Ridge, west of Chilmark. Here about 40 feet of dark grey micaceous silty clay is seen containing a nearly continuous layer of dark grey argillaceous and calcareous mudstone or silty sandstone. Small ovoid dark- coloured septarian stones are scattered through the clay, and one of these was analysed for us by Prof. J. B. Harrison, F.G.S., of Demerara, the result showing the presence of much phosphate of lime (51'6 per cent.), carbonate of iron (6 per cent.), and carbonate of lime (19 - 38 per cent.), the latter probably being chiefly from the calcite-veins which traversed the nodule. These phosphatic nodules are common in the Gault throughout Wiltshire and the northern part of Dorset ; they run from 3 to 5 inches in length, and are often 2 inches in diameter. Fitton records the following fossils from this exposure : — Ammonites Beudanti Rostellaria carinata. „ dentatus[interruptus] Pectunculus umbonatus. „ tuber culatus. Cytherea parva 1 „ seliiguinus (?) Lima elongata ( = parallela d'Orb). varicosus [? an error] Terebratula sp. Avellana inflata, Dentalum decussatum. v The Eev. W. R. Andrews inter ruptus, Am. splendens (Fi; Astacus [? Hoploparia]. himself obtained Ammonites 32), Inoceramus sulcatus and a large species of Cucullcm, probably glabra. UPPER GEEENSAND. The malmstone into which the highest part of the Gault passes is a fine-grained grey siliceous rock, containing a variable amount of colloid silica, but less than the typical malmstone of Hampshire; in other words it is an impure malmstone with considerable quantities of clay and fine sand in its composition. Some parts of it may contain 20 per cent, of colloid silica, but an argillaceous sample from Sutton Mandeville, analysed by 40 THE GEOLOGY OP SALISBURY. Prof. J. B. Harrison yielded only 11 '4 per cent., with 3184 per cent, of quartz and mica,' and 341 9 per cent, of combined silica; this sample was remarkable for containing a large amount of magnesia (818 per cent.) and no carbonate of lime. The malmstone passes up into fine micaceous sand which sometimes, as near Ridge, passes into a very soft and loose sand- stone containing much colloid silica,, a material which the French call gaize. These sands always weather to a buff or yellowish colour, but pass up into grey sands which have little or no mica, consisting entirely of small grains of quartz and glauconite. The highest part of these sands for 9 or 10 feet contain roundish concretions of calciferous sandstone, some as large as a man's head. The next member of the group is a firm glauconitic sandstone of coarser grain than the beds below, and cemented by calcareous matter into a fairly hard rock. This stone has been quarried in many places for building- material and was formerly in much request. Along the northern outcrop, and perhaps on the southern side of the Vale, there is a layer about a foot thick in this sandstone almost entirely composed of Ostrea vesiculosa, and where the rock has been much decomposed at the surface, this shell-bed becomes a conspicuous feature in it. The rock also contains Pecten asper and P. quadricostatus. The Chert Beds are a continuation of those which appear near Warminster; they consist of fine greyish sand, often almost a silt, containing large quantities of sponge -spicules, and enclosing layers of black or brown chert and of white porous siliceous-stone, with occasionally daggers of calcareous sandstone. Fossils of other kinds are rare. The highest member of the series is seldom seen in the eastern part of the Vale, but appears to consist of sharp green sand without fossils. The Upper Greensand of the Vale of Wardour is apparently no less than 150 feet thick, and includes two distinct zones, that of Ammonites rostratus (Fig. 33) and that of Pecten asper (Fig. 34) ; the older of these zones, that of A. rostratus, though here almost entirely composed of sand, is the equivalent of the Upper Gault clay of districts farther east. There are many exposures of the beds composing the zone of Ammonites rostratus on both sides of the Vale of Wardour. 'It forms the mass of what is called the Upper Greensand, and the general succession is as follows : — o Ft. In. Glauconitic sandstone (zone of Pecten asper) ... Soft greenish-grey sand with hard irreg- ular calciferous concretions (no chert) 9 Fine'greenish-grey sand, often laminated and current-headed - - about 30 Buff-coloured sands, becoming mica- ceous below and passing into soft micaceous sandstone - 50 Umpure sandy malmstone, from 15 to - 30 Gault (grey sandy micaceous marl) - The thicknesses given are approximate only, and the total probably varies between 105 and 120 feet. Zone of Am. [Schloenb.] rostratus. U*>PER GREENSAND FOSSILS. 41 Fig. 35. Fig. 36. Fig. 33. Ammonites (Schloenbaohia) Fig. 34. Pecten asper, Lam. |. rostratus, Sow. J. ,, 36. Ostrea vesiculosa, Sow. 35. Exogyra conica, Sow. 42 THE GEOLOGY OF SALISBURY. On the south side of the Vale there is a good section of the malmstone in a deep fosse-way by Sutton Mandeville church. The beds dip to the south and the top is not seen, but there seems to be a 'thickness of about 30 feet ; most of it is a light frey stone of small specific gravity, so that it feels light in the and, but some of the beds are heavier and more argillaceous with spots and streaks of dark grey marl. The stone weathers into beds of 6 to 12 inches thickness. Another excellent section of these strata will be found in the sand-pit opposite the church at Ansty, which shows 35 feet of fine glauconitic sandy loam, with a few masses of concretionary sandstone, Exogyra conica (Fig. 35) occurring in the other part, and Pecten (Neithm) quin- quecostatus, and a large Serpula in the lower. The bottom of this pit is probably 30 or 40 feet above the clayey Gault, which throws out strong springs around the pond below. Along the north side of the Vale the sandstone is well exposed by Knap Farm near Ridge, where it has the character of a true " gaize " like that of Devizes ; here it contains Serpula concava and impressions of bivalve Mollusca. It is also visible in the lane north of Dinton, The best sections through the sands which form the higher part of the zone are : — The lanes near Ridge. A sand-pit in Upper Holt, north-west of Teffont. The lane north of Dinton. Large sand-pits by the road north-west of Dinton Manor Farm. The railway cutting near Baverstock. The lane down the north side of Fir Hill, near Fovant. The zone of Pecten asper is well developed in the Vale of Wardour, and consists of the following beds : — Green sand or sandstone, from 6"to 10 feet. Chert Beds, from 20 to 30 feet. Glauconitic sandstone from 9 to 16 feet, the average thickness being probably about 45 feet. The glauconitic sandstone is exposed in many of the lanes and roadways on both sides of the Vale, and its thickness increases from 9 feet on the western side to 14 or 16 feet towards the eastern end. In the middle or upper part of it there is a layer about 12 inches thick which consists almost entirely of Ostrea vesiculosa (Fig. 36) shells, and where the rock has been decom- posed into soft sand and sand-rock this bed of Oyster shells becomes a very conspicuous feature. The stone has been quarried in many places for building- material, and was formerly in much request. Dr. Fitton says it was called " Greenstone ' at Fovant, and adds " it is valuable from its not being affected by frost. It can therefore be dug at any season, and stands well in water as in the foundations of bridges, and in exposed situations as in copings, etc."* The Chert Beds are used for road-metal around Swallowcliffe, The best section on the south side of the Vale is that of the okl quarry at Fovant near the Pembroke Arms. Dr. Fitton gave * Trans. Geol. foe. Ser. 2, vol. iv., p. 246. GATJLT AND UPPER GREENSAND. 43 o M M CO w M 1-5 3. 2" If 3 o -& -to ?° cS E~ -S -y s 8 O R5 •3 ■« S y .* .5 "■^ "» a g t»H u o §> 3 § &0 *»& a 8 4> ^ c ^3 C5 Wi « i/!/l 'PI M ■ Ll (•>.V: be H » IO 1 ■* Pq i—f sq 1 lO B i O e ■ 0) , « OB 1 'm © ' T3 i 8 CB > §i 03 £ bo-d oq & 3 S-i T3 ft 13 h M ft &< H PR tD 00 o s ft t a c3 o T3 I a o +3 O o ft o ° "3 m 9 S IPg » 0) i jh « >a i i)- © *-l g w DQ gj Ph h1 . ^ spagmaqQ-g 44 THE 'GEOLOGY OF SALISBURY, the succession here, and his account differs little from the following, which was taken in 1890 : — Feet. Soil and Bubble - - - -. 3 Fine grey silty sand, with layers of chert and white porous siliceous stone - - - - 8 Soft grey sand, with two layers of greenish calcareous stone 4 Soft grey sand, with nodular lumps of calcareous grit, passing down into tough greenish sandstone with irregular lumps of hard grit - - - - - 6 Firm greenish sandstone, standing with a vertical face and weathering yellowish brown - 10 31 The only fossils seen in the' sandstone were Pecten orbicularis and Ostrea vesiculosa, but Dr. Fitton also mentions Sharks' teeth. The beds are nearly horizontal, and form part of a plateau, which has a gentle slope to the southward. The stone is rather coarse in grain, the glauconite grains being large, dark green, and conspicuous. The highest oeds of the Greensand are well exposed near Baverstock. In the wood about half-a-mile east of the church is a small sand-pit, which shows marly glauconitic sand (about 3 feet) passing down into sharp bright green sand (about 8 feet). This must be just below the " Chloritic Marl." In the railway cutting to the south-eastward lower beds are seen with a dip of about 10" to the north-east, by which the succession shown in Fig. 37 is brought in. At two other points within the area described in this Memoir the higher beds of the Upper Greensand are exposed at the surface, but there is no section visible. One exposure is at Alvediston, the other farther east, near Mead End. The last- mentioned outcrop is part of the Greensand inlier brought up by an anticline which runs through Bower Chalk ; sections in this Greensand will be found in Bower Chalk village, which lies just outside our limits (see Ringwood Memoir and Map, sheet 314). CHALK. 45 . CHAPTER VIII. CHALK* The Chalk,- which occupies the surface over so large a part of the area described in this Memoir, forms a mass of such great thickness that it has been mapped in three sub-divisions — Upper Chalk (soft, with flints), Middle Chalk (harder and less flinty), and Lower Chalk (grey marly chalk without flints). In addition to these broad lithologieal divisions, various zones characterised by peculiar fossils have been recognised, though it has not been attempted to lay down these palseontological zones on the map. The zones usually .recognised are as follows :-^ Upper Chalk (with Chalk Rock at its base). Middle Chalk (with Melbourn Rock at its base). Lower Chalk (with Chloritic Marl at its base). Zone. /Belemnitella mucronata Actinocamax quadratus Marsupites testudinarius Micraster coranguinum cortestudinarium Holaster planus C Terebratulina -j Rhynchonella Cuvieri (=zone I. Inoceramus labiatus) Holaster subglobosus Ammonites varians Thickness. Ft. 80 170 230 240 f 70 of 80-100 90 100 about 1070 The upper part of the series is incomplete, only the base of the BelemniteUa mucronata zone being preserved, and this only in the neighbourhood of the Eocene strata. LOWER CHALK. The nodular and phosphatic Chloritic Marl, which forms the base of the Chalk in- this part of England, is nowhere clearly exposed within our area ; but the rest of che Lower Chalk forms a well-marked belt of undulating marly land, fringing the Vale of Wardour and running at the foot of the scarp which every- where bounds the valley. Lower Chalk also appears in the bottom of the valley of the Wylye around Codford, and again on the southern limit of the district around Alvediston and Broad Chalk. A good exposure of the alternating beds of soft marl and hard chalk forming the upper part of the Am. varians zone occurs in the chalk-pits by the side of the road leading up Buxbury Hill, on the south side of the Vale of Wardour, and is seen in the * Mainly from the notes of Messrs. A. J. Jukes- Browne and F. J. Bennett, 46 THE GEOLOGY OF SALISBURY. lowest level leading to the door of the lime-kiln, the descending succession being as follows : — Ft. In. Two courses of hard rough grey chalk separated by loose marly chalk - - - 2 6 Dark grey argillaceous marl 6 Loose grey marly chalk - - 1-3 Hard grey chalk - - from 9 inches to 1 6 Marly grey chalk, weathering into loose fragments, with here and there patches of darker blue grey chalk (many fossils) - - - 14 Very hard rocky grey chalk, rising from below the last near entrance - - 16 Dark grey tough marly chalk seen for 1 22 3 These beds have a southerly dip of 4°, and contain many of the characteristic fossils of the Chalk Marl, such as RhynchoneUa Martini, Rh. grasiana, Lima globosa, L. aspera, Ammonites [Schloenbaghia] varians, etc. A quarry to the south-east of the village of Fovant shows a similar set of ..beds, which must be at about the same horizon. The upper part of the quarry is in firm, massive, whitish chalk, of which about 50 feet is seen, and below this the following succession can be made out :— Ft. Hard greyish-white chalk in layers, having alternately a rough and a smooth fracture 6 Layer of soft grey marl - Hard grey chalk - - 3 Soft dark grey marly chalk - 1 Dark grey sandy chalk, with visible grains of glauconite (many fossils) - about 15 Very hard light grey limestone 1 Soft grey marl below. The grey sandy chalk is not unlike Totternhoe Stone, and contains many of the same fossils, but there are no phosphatic nodules or fragments in it. There are no good exposures of this zone on the north side of the Vale of Wardour. By the road leading up to Buxbury Hill there are two excava- tions in the higher part of the Lower Chalk. The first of these is in the quarry above the exposure by the limekiln previously mentioned. This shows about 25 feet of firm blocky greyish- white chalk, breaking as usual along more or less curved surfaces, so that the real planes of bedding are obscured. The following fossils occurred: Ammonites [Acanthoceras] rotomagensis, Inoceramus sp., Ostrea lateralis, JPeclvn Beaveri, Terebratula semiglobosd, and Mr. Rhodes subsequently found Ammonites [Acanthoceras] Mantelli, Am. [ffaploceras] Austeni (?) (a frag- ment), Ostrea vesicularis, and Pecten orbicularis. These species and the absence of Ammonites varians suggest that these beds belong to the higher zone. If this is correct, the floor of the quarry nearly coincides with the transition from one zone to the other. CHALK. • 47 On the other side of the road, and at a little higher level, there is a second quarry, showing the following beds : — ■ Ft. Compact white chalk, weathering into courses with looser chalk between thetn - 5 Kather rough greyish- white chalk 6 Marly parting. Hard greyish chalk, with indefinite bands of very hard nodular grey chalk - - - - 8 Massive compact blocky chalk, parting along curved surfaces seen for 7 26 The lowest blocky chalk is evidently a continuation of that in the other quarry. The nodular beds contain Ammonites Austeni (?) and Swssexiensis (?). They show a dip of 6° or T to the south-east. The marls of the Act. plenus band cross the road about 100 yards farther up, and from them Mr. Ehodes got three specimens of the characteristic Belemnite. A quarry by Pitchpenny Clump, north of the hamlet of Kidge, shows the Melbourn Rock resting on a layer of grey marl, with greyish chalk below, but the rest of the section was obscured by talus when visited in 1890. A similar section is exposed in a chalk-pit about a mile north- east of Dinton, grey blocky chalk succeeded by a broken layer of grey marl passing below the Melbourn Rock, which dips north at about 20°. No sections of Lower Chalk are visible in the part of the Wylye Valley that comes within our area, though immediately west of the limits two pits will be found. At the southern margin of the area the Lower Chalk is again brought up by anticlinal folds, and is seen here and there in the Ebble Valley. In these inliers Mr. Bennett has noted a few sections. In the Broad Chalk inlier a . pit will be found above Knighton Farm, and a road-section half a mile south of Croucheston. The Bower Chalk exposure shows several sections ; the only ones which come within our limits are, however, those near Mead End. The soring-head south of that farm shows hardish grey flaggy chalk with Ammonites varians. A pit nearer the farm shows 10 feet of rather hard flaggy chalk, apparently higher in the series, having a northerly dip of 8°. No pits are now open at Alvediston. MIDDLE CHALK. The Middle Chalk, from its harder character, tends usually to form the lower part of the steep scarp which borders the valleys where the softer Lower Chalk occupies the bottom. In other places the contours where Middle Chalk appears at the surface are scarcely distinguishable from those of the rolling downs which characterise the Upper Chalk. The soil of the Middle Chalk is dry, and more fitted for pasture than for tillage, for where the slope is steep the soil tends to wash away during heavy rains. It is unfortunate that these steep slopes were ever 48 THE GEOLOGY OF SALISBURY. ploughed, as the removal of the turf allowed the rain to wash away the thin soil which had taken centuries to accumulate ; and now the absence of soil is severely felt. The total thickness of this division is, as already mentioned, about 80 or 100 feet. At its base is a band of hard nodular rock, known as the Melbourn Eock, having a thickness of 5 or 10 feet. Two palaeontological zones are included in the division, that of Jihynchonella Cuvieri above, and that of Terebratulina below ; fossils, however, are not abundant in the Middle Chalk of this district, the most common being the fibrous fragments of an Inoceramus, probably the species variously known as I. mytiloides or I. labiatus. This shell is usually accepted on the continent as giving the name to the zone here knoWn as that of Rhynclio- nella Cuvieri. The main outcrop of Middle Chalk within our area is that bordering the Vale of Wardour ; but the rock covers also a considerable area in the valleys of the Wylye and Ebble. In the Vale of Broad Chalk, many exposures of Middle Chalk can be found, but, according to Mr. R J. Bennett, there are few large quarries in it. He saw the Melbourn Rock at Broad Chalk, at the top of a quarry north of Chalk-pit House, and again in the road south of Knighton. Mr. Jukes-Browne visited Homington and Coombe Bissett in 1890 ; south of Homington he found a quarry in the Cuvieri zone, showing : Ft. Hard chalk, broken and weathered, with two layers of greenish marl, Inoc. mytiloides - - - 6 Hard whitish nodular limestone - seen for 6 In the lane leading out of the road from Homington to Coombe the top of the Lower Chalk (with the Belemnite marl) overlain by hard- Melbourn Rock are well seen. At Coombe Bissett there is a large pit in the lower part of the Middle Chalk about 40 feet deep ; the chalk at the bottom is hard, and contains Inoceramus mytiloides; higher up, it is tough and massive, with several layers of soft marl ; and near the top are many grey flints. The beds are dipping to the north at about 4 deg. The sections of Middle Chalk around Ebbesborne Wake and Alvediston are not important, though a pit by the road-side half a mile west of Alvediston church shows 10 feet of hard thick- bedded chalk with marly bands. A similar section can also be seen in a pit at Prescombe Farm. There are no good quarry sections in this division along the south side of the Vale of Wardour, but the whole of the Middle Chalk can be traced in the roadway ascending Compton Down ; first, the rough nodular chalk of the Bhynchonella Cuvieri zone, then the firm white chalk of the Terebratulina zone overlain by the hard rocky beds of the Chalk Rock. South of Barford, in the road cutting leading to Hoop Side, the Melbourn Rock can be seen overlying the highest beds of the Lower Chalk, OHALK. 49 Along the northern border of the Vale of Wardour there are a few places where the zone of Rhynchonella Cuvieri can be seen in spite of the high dips. A quarry north-east of Baverstock shows about 25 feet of this zone, hard, rough, and nodular in the lower part, which cannot be far from the Melbourn Rock. The two common fossils were found in the upper beds, and the dip is about 33 deg. to the north-east. The Melbourn Rock, passing up into hardish bedded chalk containing Rhynch. Guvieri, and Inocerainus mytiloides, is also exposed in a small pit threequarters of a mile north-east of Dinton. The dip here is about 20 deg. north, and an old excavation close by must have shown the Terebratulina zone, as the. Chalk Rock, which is still exposed at the northern end, dips at 45 deg. A quarry half a mile north of the village of Ridge shows the following section : — Ft. Hard bedded whitish chalk - - - 15 Hard yellowish nodular chalk in regular beds, with several layers of marl - 10 Marked layer of marly chalk - Hard nodular yellowish chalk (Melbourn Rock) 5 Oreenish grey marl and marly chalk 6 Talus concealing lower beds. The dip here appears to be about 15 deg. to the north. Mr. F. J. Bennett states that the rock is seldom well exposed in the Wylye Valley, but he saw exposures of it in an old lane south of Boyton, and again south of Sherrington in an old trackway leading eastward. Hard bedded chalk, which probably belongs to the zone of Rhynchonella Guvieri, is to be seen in the road-cutting at Deptford and in a chalk-pit by Deptford Field Barn. UPPER CHALK. Over more than half the area which is now being described the surface rock is Upper Chalk. This division is 700 or 800 feet thick, so that hills and valleys of considerable size can be carved out of it without .any other rock being exposed. Most of the wide expanse of Salisbury Plain, only part of which comes within our area, is Upper Chalk, and this plain is continued eastward in the plains of Basingstoke and Winchester, which again stretch eastward to the sea m the two long tongues known as the North and South Downs. In the southern part of our area the continuity of the Downs is somewhat broken by the Alderbury syncline, the trough of which brings in Eocene strata ; but south of this tongue the continuity of the Downs again stretches unbroken into Dorset and to the English Channel. In its character and composition this great mass of rock is singularly uniform ; nearly all of it is soft white chalk, with flint nodules scattered more or less in lines. One or two thin hard bands, known as Chalk Rock, occur at the base, and an occasional marl" parting is found; but lithologically it is all one formation, 6152, . E 50 THE GEOLOGY OF SALISBURY. and we have been obliged to map it as such. When we examine fhe fossils, however, it is found practicable to break up this mass into zones characterised by peculiar assemblages ; but the limits of these zones are somewhat indefinite, for the species -in most cases disappear one by one and are replaced equally gradually by the species of a higher zone. No sudden transitions from one fauna to another have yet been discovered in the district with which we are dealing. In other regions, however, breaks, marked by lines of nodules, which suggest either the non-deposition or the destruction of certain intermediate strata, can be found ; and at the same points a sudden change in the fauna usually takes place. The area occupied by the Upper Chalk is shown on the map, whereon the outcrop of the Chalk Rock has been delineated. It will be seen that this is an extremely irregular line, running for a long distance down the valley of the Wylye, and then westward till it climbs to a very high level on White Sheet Hill, north of Mere. On the south side of the Vale of Wardour the lower beds of the Upper Chalk form the highest part of the ridge, which ends in another White Sheet Hill, east of Shaftesbury, a ridge which separates the Vale of Wardour from the Vale of Broad Chalk. The structure of the latter is clearly shown by the mapping of the Chalk Rock, and proved to be a succession of dome-shaped uplifts (three or four) arranged along an anticlinal axis. This axis is prolonged eastward across the valley of the Avon, and is continued in the tract. of chalk which indents the boundary of the Eocenes north-east of Downton. From this anticlinal axis the Upper Chalk dips northward under what may be called the Salisbury syncline, and southward into a wider main syncline of the Hampshire basin. It is only in the eastern part of this area, near Salisbury and Downton, that any great thickness of Upper Chalk comes in. In most other parts of the district no higher zone than that of Micraster coranguinum is found. In describing the local development of the several zones, it will suffice to give particulars of some of the best exposures of the lower zones, and then to concentrate our attention on the neighbourhood of Salisbury. In South Wiltshire the zone of Holaster planus has the true Chalk Rock aspect, always containing two or more beds of hard compact yellowish limestone with layers of green- coated nodules. It is not often, however, that the whole of the Chalk Rock beds are exposed in one section, and a visit to some localities might lead the observer to believe that there were only a few feet of such rock. More complete sections, however, show that the harder rock beds often pass down into less hard and more nodular chalk, forming a set of beds which are from 12 to 16 feet thick. In other places the group expands by the inter- calation of separate beds of lumpy chalk, some of which are hard, and others consist of hard lumps in a soft mealy kind of chalk ; the whole group is then from 20 to 26 feet thick, always having a hard rock-bed at the ba.se a,nd another at the top. OHALK. 51 Above the uppermost beef of rocky chalk we find softer but still lumpy chalk containing many flints, and often thin seams of flint, while there are no flints in the Chalk Rock beds. These higher beds contain Micrasters of the cortestudinarium type, and may be referred to the zone of that species ; but other fossils are few. There are few good exposures of this zone, and its upper limit has nowhere been satisfactorily fixed, but it is supposed to be 40 or 50 feet thick in the valley of the Wylye. The succeeding zone of Micraster coranguinum is, as usual, of considerable thickness (more than 200 feet), and is believed to occupy the larger part of the surface area of Salisbury Plain ; it also occupies some space west of Salisbury and north of the Vale of Wardour. Its lower beds contain many carious flints, often of a reddish tinge inside, its middle part black flints with a milky white band, and the upper beds grey flints with a thick white crust or rind. The only part of South Wiltshire in which the higher zones of the Upper Chalk have been carefully studied is the neighbour- hood of Salisbury. This was described in 1876 by Professor Barrois.* Dr. H. P. Blackmore, of Salisbury, has been collecting for many years from all the quarries within a radius of five or six miles, and has kindly placed the results of his labours at our disposal. Mr. Jukes-Browne had the further advantage of visiting most of the exposures near Salisbury under his guidance in 1890. It is from these materials that this account of the upper zones has been compiled. The total thickness of Upper Chalk exposed in this district is between 700 and 800 feet. The following estimates of the thick- ness of the several zones are based on information communicated by Dr. Blackmore : — . Feet. Zone of Belemnitella mucronata about 70 to 80 „ of Actinocamax quadratus ,,170 „ of Marsupites - „ 230 „ of Micraster coranguinum - „ 230 to 250 Zone& of Micraster precursor and Holaster planus „ 70 About 790 The facts on which these estimates are based are as follows, all the information being communicated by Dr. Blackmore. The zone of Holaster planus is seen to be over 20 feet thick near Homington, and 45 feet is probably a low estimate for the zone of M. cortestudinarium, so that the two together may be put at 70 feet. The quarry on Camp Down, between the valleys of the Wylye and the Avon, is 200 feet above the rivers ; this quarry is in the M. coranguinum zone, and the beds are horizontal, while its base is probably at about the level of the Avon stream. Hence there is over 200 feet of this zone. * Kecherohes sur le Terrain Cretac6 Sup^rieur de l'Angleterre et de l'lrlande, pp. 54, 64. Mim. Soc. GM. du Nord. 1876. 6152, js 2 52 THE GEOLOGY OF SALISBURY. From the top of Bishopsdown (north of Salisbury), where Marsupites are found, to the top of the well at the waterworks nearer the town is 100 feet ; the well was sunk 70 feet, and bored for another 63 feet, and a good Marsupite plate was obtained from the lowest part of the boring ; hence the thickness is at least 230 feet. This is confirmed by a well sunk at a spot about 2£ miles to the N.E. of Bishopsdown. , This was sunk to a depth of 230 feet, and a Marsupite plate was obtained from the bottom. With respect to the Actinocamax quadratus zone, two wells have been sunk between Harnham Hill and the river, through chalk with 'thin-skinned- flints, and fossils like those at Highfield (Marsupites zoneY From the top of the wells, to the top of Harnham Hill is 170 feet, and there is reason to think,. from the space elsewhere occupied by the Act. quad/ratios zone, that 170 is about its full thickness. As to the Bel. mucronata zone, a well has proved 63 feet of it, and from the space it occupies.it is not likely to exceed 100 feet, so that from, 70 to 80 feet is a probable estimate. Chalk Rock and Associated Beds. , The Upper Chalk is so thick, and extends over so wide an area, that it will be described most conveniently in successive stages or zones. We will therefore begin with the Chalk Rock and the associated beds of the valley of the Wylye, in which valley the outcrop has been traced for a long distance by Mr. Bennett, from whose notes the following description is mainly compiled. One of the best sections, exposing 13 feet of chalk with flints, and 8 feet of yellowish rocky beds, can be seen in the yard of a barn north of Upton Lovell. There are other sections near Codford, Sherrington, and Wylye, but the most complete one in this valley is the. quarry at Steeple Langford, about 360 yards E.N.E. of the church. We are indebted to the Rev. W. R. Andrews, F.G.S., for the following description, and for the photo- graph'from which Fig. 38 has been drawn. The upper part of the Chalk Rock can also be seen in the river cliff about a quarter of a mile north-west ofWishford church, 10 feet of the rocky beds with "green-coated nodules being overlain by 12 feet of nodular white chalk containing five layers of nodular flints, and three continuous layers or flint floors. These 12 feet may be referred to the zone of M. cortestudinarium. A quarry just east of the cross roads at Stapleford is probably opened in the latter zone. Mr. Bennett states that it is about 20 feet deep, and combining his account with that given of it by Dr. Barrois, the section, now much talused, appears to have been : — Ft. Hard white chalk with a few black flints and several flint seams, Cidaris mbvesiculo&a and Micrdster cortestudi- narium - 10 Hard nodular chalk with yellowish stains - 3 White chalk with flints, both nodules and continuous floors, talused, but dug for - , ■' r CHALK '■ J- ' .■■V-T^^.vi'.WM TT. ^p**S5|| --■ T/fX-rh-i Ft. In. 5 4 4 6 1 4 chalk 4 6 - - 3 seen for 6 About 30 Fig. 38. — View of Quarry at Steeple Langford. 1 & 2. Soft white rubbly chalk with a few scattered black flints and a layer of such flints at the base 3. Very hard nodular yellowish limestone, with many green-coated nodules, passing down into less hard nodular chalk - - 4. Similar hard limestone with nodular chalk below 5. Course of hard rocky chalk 6. Rock and nodular chalk, like No. 3 - - 7. Rock as before, passing down into less hard nodular chalk 8. Thin layer of grey marl - 9. Massive white chalk Nos. 8 and 9 belong to the zone of Terebratidina. What appears to be the summit of this zone, and its junction with that or M. coranguinum, is exposed in a quarry at the north end of Wishford ; the following is Dr. Barrois' account, with the thicknesses corrected by Mr. Bennett : — Ft. Soft whitechalk with many layers of flints and several flint seams, also joints filled with flint. Echinocorys gibbus and Micraster corangwinv/m - - 15 Hard yellowish nodular chalk - \ Rather hard chalk with scattered flints - - 6 Chalk which may be in or at the top ol the same zone is ex- posed also hi the valley of the Avon between Lower and Upper 54 THE GEOLOGY OF SALISBURY. Woodford. At Middle Woodford there is a large pit, which has been described by Dr. Barrois (" Kecherches," p. 53), and of which Mr. Jukes-Browne took the following notes in 1890 : — Ft. Soft white chalk with many layers of flint nodules, and some large masses of flint - 24 H ard yellowish nodular chalk with marked plane of division at top - 2 Hard yellowish nodular chalk, with nodular upper surface, enclosing many flints of irregular shapes and often hollow, with Doryderma ramosa - 2 Softer white chalk with numerous flints and a seam of con- tinuous flint - 10 The beds are nearly level, with a slight inclination to the south. Fossils are fairly abundant, and from the nodular beds and the underlying chalk Mr. Jukes-Browne obtained a species of Micraster, Gidaris clavigera (spines), Echinocorys gibbus, Terebratula semiglobosa, and Rhynchonella reedensis. Mr. Bennett after- wards obtained a specimen of Coscinopora infundibuliformis. It is possible that the upper beds may belong to the zone of Micraster coranguinv/m, in which.- case the nodular chalk may be regarded as the top of the M. precursor zone. Another good series of sections in the zones oiHolaster planus and Micraster cortestudinarium, can be found along the north border of the Vale of Wardour from Mere to Barfdrd, and have been noted by Mr. Jukes-Browne. At the eastern end of the Vale, on the downthrow side of the fault, the Chalk Rock beds are well exposed in tbe railway cutting at Barf ord. The descending section here, taken about 90 yards from the west end of the cutting, is as below : — Ft. In. Hard lumpy chalk with scattered nodules of black flint, very gritty and yellowish in some places (? zone of M. cortestudinarium) - - - 12 Hard and heavy nodular limestone with yellow stains, in two layers, the upper full of green-coated nodules - 1 3 Hard yellowish limestone passing dowji into hard rough nodular chalk - - 3 4 Parting of white shaly chalk. Hard nodular chalk - 1 3 Hard yellowish limestone with a layer of green-coated nodules at top, passing down rough lumpy chalk. Ter. carnea and Micraster - 7 Soft yellowish-grey marl - 3 Rough nodular chalk with yellow stains, very hard in places, same fossils - - 4 6 Parting of buff shaly marl. Nodular white chalk with two layers of grey sandy and shaly chalk - - 4 6 Hard nodular limestone with a layer -of green-coated nodules, probably the bottom bed of Chalk-rock seen for 3 37 1 CHALK. 55 It will be seen that the zone of Holaster planus or Chalk Rock . has here a thickness of over 25 feet. The thickness of the over- lying lumpy chalk.is uncertain, but in the cutting east of the bridge 5 feet of it are seen overlain by soft white chalk with four continuous layers of flint, and as the upper rock bed occurs at the base of this cutting there is probably from 15 to 16 feet of the lumpy chalk between, containing Micrasters of the M. cortes- tudinarium type. Partof the same set of beds is exposed on the south side of the valley in the road cutting at the head of the " Punch Bowl," near Burcombe. Here the upper beds are much weathered, but the junction with the zone below is clearly exposed, the section seen in 1890 being as below : — Ft. In. /-Hard compact yellow limestone 1 6 Hard rough nodular chalk 10 Layer of soft marl. Zone of Hard rough nodular chalk with yellow stains 6 Hol.planus > Tough gritty whitish chalk, splitting into (26 feet). flattisji lumps with lenticular seams of greyish marl - about 5 Hard nodular rock with two layers of green- coated nodules ; passes into next - 3 6 Zone of f Tough and lumpy white chalk - 5 Tere- I Seam of light grey marl 4 bratulma. \ Bedded white chalk - seen for 3 » This section, therefore, gives the base-line which is wanting to complete that of the Barford cutting, and shows the full thick- ness of the Hoi. planus zone to be just 26 feet. The rocky beds of the H. planus zone are seen in several of the roadways which ascend the fine escarpment along the southern side of the Vale of Wardour, as, for instance, in the roads south of Compton and of Fovant, a pit by the latter exposing 11 or 12 feet of them. Passing to the Vale of Broad Chalk by way of Compton Down, the outcrop is again passed through about three-quarters of a mile north of the village. Here Dr. Barrois noted 30 feet of hard nodular chalk overlying a bed of Chalk- Rock with green-coated nodules, and from the former obtained the following fossils :— Micraster cortestudinarium. Inoceramus Cuvieri ? „ corbovis? [Leskei] Terebratula semiglobosa. Mr. Bennett states that it is also exposed in a quarry west of Prescombe Farm, north-west of Broad Chalk. It is also fairly well shown in the road-cutting north of Homington, where the hard, yellowish basement rock is seen to dip northward at about 8 deg., and to be overlain by about 20 feet of nodular rock, with some scattered flints and another hard bed at the top. From this exposure Dr. Blackmore has obtained the following species : — Inoceramus sp. . Terebratula semiglobosa. , Ostrea vesicularis. Ehynchonella reedensis. Spondylus spinosus. , Holaster planus. Terebratulina gracilis (? var. lata). Parasmiha centralis. ,, striata. 56 THE GEOLOG"? OF SALiSBUKV. Zone of Micraster corangwinum. The 'quarry at Middle Woodford, north of Salisbury, has been described on p. 54, and the probability of its being opened at the junction of the zones of Micraster precursor and M. coran- guinum was then mentioned. There is a small pit at Little Durnford, on the eastern bank of the Avon, which exposes chalk with many layers of thin-skinned flints, most of them stained red or reddish with iron oxide; this is certainly in the zone of Micraster coranguinum, that fossil and Echinocorys scutatus being common here. A pit at the north end of the village of Stratford shows some 25 feet of firm but brittle white chalk, with layers of flints at intervals of from 1 to 3 feet ; these flints have thin skins, and many are cavernous (caries), the hollows showing traces of Doryderma ramosa, and some have drusy cavities filled with quartz crystals. Several layers, however, consist of solid flints stained red or brown by iron. Micraster coranguinum, Galerites albogalerus (Echinoconus conicus), Cidaris hirudo, Ostrea semi- plana, Inoceramus Ouvieri, and other fossilsliave been found here. Another pit on the northern side of Old Sarum hill is about 80 feet above the floor of the other, and shows softer chalk with scattered flints, not in layers, and less numerous. These flints have thick rinds, which are banded in layers of white and grey, and are solid throughout ; the smaller nodules have, in fact, only a small nucleus of clear black flint, but both the black and the white parts are equally hard. This chalk is probably near the top of the zone. On Camp Down, between the valleys of the Avon and the Wylye, there is a large pit near the mam road showing 25 to 30 feet of chalk with similar thick-rinded flints, many of them show- ing pink, white, and grey bandings, and being of very irregular shapes with knobby or cornute projections. Fossils are scarce, but twenty species have been found by Dr. Blackmore and Mr.' E. Westlake, and prove it to be in the M. coranguinum chalk, though it must be near the top of that zone. The zone of Micraster coranguinum probably occupies a large part of the surface of Salisbury Plain, and is deeply trenched by the rivers which traverse that plain. West of Salisbury it also occupies some space round Quid- hampton, Wilton, and Netherhampton. At Quidhampton there is a large pit on the north side of the railway, showing between 50 and 60 feet of chalk. Flints occur in regular courses, which are from only about 2 feet apart in' the upper 40 feet, but more distant in the lower part ; most of them have very thin rinds, some hardly anything but a white skin, but a few have a definite white crust ; some are large with irregular knobby surfaces. The bedding is nearly horizontal. From the lower beds Mr. Jukes-Browne obtained Micraster coranquinum Epiaster gibbus, Terebratula carnea, Inoceramus Guvieri, Lima Hoperi, and Ostrea vesicularis, and Dr. Blackmore has found a few other species. CHALK. 57 The higher part of the zone is exposed in a pit by the Roman road south of Netherhampton. When seen in 1890, much of it was hidden by talus, but above this, chalk with numerous flints is seen like that at Camp Down ; the flints have the same pink and white chalcedonic layers in the outer crust. Some of the usual fossils of the zone have been found here. South-west of Salisbury, in the valley of the Ebble river, a portion of the central part of the zone is exposed a little south of Odstock, dipping to the north at about 9°. The chalk is firm, white and brittle; flints occur in frequent layers about 2 feet apart, and nearly all of them have a band or zone of cloudy white flint a little distance beneath the external surface, but little or no crust. Fragments of large Inocerami are common, but other fossils are rare. In ascending -Clea'rbury Hill from Charlton a definite succession of beds may be recognised from the characters of the flints seen in small pits and roadside banks. Thus a quarry opposite Charlton Farm is about 30 feet deep in rather hard chalk, with many solid plain black and dark grey flints, and fragments of Inoce- ramus shells are abundant. A pit about a quarter-mile to the « south-west shows about 16 feet of chalk, with crowded layers of irregular shaped flints about 2 feet apart, and most, of them have the cloudy white zone above mentioned, but some are stained red or pink by iron. Higher up on Clearbury flints with the same cloudy band are seen, but near the top of the hill they have thick crusts like those at Camp Down. A quarry in the lower part of this zone, north of tJfford, shows some interesting features; it is about 20 feet deep in well-bedded chalk, which shows a dip of about 2° to the south-east. The descending succession is as follows : — Ft. In. Chalk, inaccessible 8 Continuous seam or floor of flint 1 Firm solid chalk without flints - ■2 Soft loose marly chalk crowded with flints 1 Solid bedded chalk, with few flints 4 Soft marly chalk 6 Chalk with many scattered flints 8 23 7 The beds are broken by a small fault with an oblique hade and a throw of about 4| feet. The flints, both large and small, have either a thin crust or none at all. Fossils found were Micraster coranguinum, Galerites albogalerus (Echinoconus conicus), and Inoceramus involutus. The upper part of the M. coranguinum chalk is exposed in the rail cutting at Witherington, north of Downton, and the beds, which correspond with those at Camp Hill, dip at 14° to the south, and there arc other places on the eastern side of the Avon. On the western side of that river its basset surface must occupy a considerable tract of country south of the Broad Chalk valley. 58 THE GEOLOGY OF SALISBURY. Zone of Marsupites. The chalk of this zone occupies the higher ground in the im- mediate neighbourhood of Salisbury, as' on Bishopsdown, Milford, and Fisherton. The lower part of the zone is well shown in the quarry at the whiting- works at Fisherton ; this is about 50 feet deep in pure soft white chalk; flints are not numerous, but occur sparsely along planes which are about 10 feet apart. Most of them are nearly spherical, from the size of bullets to that of cannon balls, are yellow outside, but have . no crust, merely the yellow stain, and consist wholly of solid black flint. The workmen state that they have quarried about 12 feet below the then pit floor, and found the same kind of chalk. Actinocamax verus, small Kin- gena lima, and the ovate variety of Echinocorys scutatus are common here. Uintacrinus and a few of the brachial joints of Marsupites have been found, and twenty-five specimens of Ammonites [Haploceras] leptophyllus, with other fossils. ' The higher part of the Marsupites zone is exposed in a pit on Bishopsdown, which shows soft white chalk, with more numerous Hints, all having thick white crusts. Plates of Marsupites and joints of Bourgueticrinus are very abundant at this locality, and a specimen of Am. [Hapl.] leptophyllus about 2 feet in diameter was found in 1893. In that year also a well was sunk at the foot of Bishopsdown, and nearly 100 feet below the quarry; Dr. Blackmore informs me that the well is 70 feet deep, and traversed chalk with occasional layers of flints exactly like those of High- field. The first layer met with was 45 feet from the surface, and one Marsupites plate was found in the lower 30 feet. This information is important, as proving the Highfield chalk to be inferior to that of Bishopsdown, and as giving a thickness of at least 170 feet for the Marsupites zone. Zone of Actinocamax quadratus. The Actinocamax quadratus zone forms the. high ground to the east and north-east of Salisbury, and also the ridge which lies to the south of the villages of East and West Harnham. It consists of chalk, in which flints are rather more numerous than in the Marsupites zone, and in the lower part of it Offaster pillula is the most common fossil. At East Harnham there is a fine quarry worked in two levels. The lower one shows about 50 feet of bedded white chalk, with only a few scattered flints ; the upper level shows about 60 feet, with seven or eight layers of flints at varying distances, some- times 6 feet, sometimes 10 or 12 feet apart, with only a few scattered flints in the intervening chalk; The beds are regular, and dip at about 2° to the south, unbroken by faults. The "flints have white crusts, but not thick ones, and are all solid. Fossils are not abundant, but, through the workmen, Dr. Blackmore has obtained many species from this pit. At West Harnham there is another large quarry from 60 to 70 feet deep. In the higher j>art the chalk is regularly bedded ; in the lower part the bedding is less distinct, and it is probably a chalk;. 59 lower portion of the zone, for the flints, few and scattered, are stained yellow outside. Act quadrata is fairly common in the upper part, but rare in the lower beds, though it has been found in them. At Britford a quarry shows about 30 feet of the higher beds, bedded chalk, with layers of flints at intervals of about 3 feet, and sometimes less. East of Salisbury there is a small exposure of the lower part of the zone at the cross-roads east of Milford, but, though only 10 or 12 feet of chalk, are exposed, many specimens of Offaster pillula can at any time be obtained, with joints of Bourgueticrinus and a small Rhynchonella (? reedensis) ; the shelly plates which are usually regarded as the aptychi of Ammonites [Haploceras] leptophyllus and of Am. [Pachyd ] Portlocki, and which Dr. H. P. Blackmore regards as shelly processes belonging to the guards of Belemnitella tanceolata and Actinocamax quadratus, have been found here as well as at the Harnham quarries, and are certainly as common in this zone as are the two characteristic Belemnites. Part o£ the same zone, with flints like those of Harnham, is exposed in the railway at Ashley Hill, and in the pit below the level of the railway, north of Ashley Hill House, Dr. Blackmore has also traced the zone at intervals for some distance to the north-east, and has found a piece of Act. quadratus thrown out of a rabbit hole on the hill known as Thorny Bushes. South-east of Salisbury there is a good section of it in the rail- way cutting at Whaddon, which shows soft white chalk, with irregular layers and scattered nodules of flint, and occasional seams of soft marly chalk dipping to the north at about 14°. The flints have thicker white crusts than those of Harnham, but there is the same assemblage of fossils. A quarry in the field near the railway is about 15 feet deep in similar chalk. At West Grimstead, south of the brickyard, there is another pit in similar chalk dipping at 16° to the north. It contains, however, regular layers of flint at 3 or 4 feet apart, many of the nodules being large and smooth, with rounded protuberances ; • they have thick crusts, often pink and agaty, like those of Camp Down. Fossils did not appear common, but Act. quadratus was found. Zone of Belemnitella mucronata. This, the highest zone of the chalk in the Hampshire basin, is only found round the border of the area occupied by the Lower Eocene to the east and south-east of Salisbury. It is exposed in a chalk-pit at Shootend, north-west of Alderbury, between the branching of the roads to Downton and to Southampton. The Chalk here seen is very soft and white, with few flints, those that occur consisting of 'solid black flint without any crust — merely a yellow coating. Belemnitella mucronata is fairly common, with Echinocorys scutatus, Terebratula carnea, Rhynchonella limbata, a large variety of Kingena lima, and other fossils similar to those found in Norwich chalk. More recently Dr. Blackmore 60 THE GEOLOOJY OF SAtlSBUM. has found Magas pumilus and pieces of an Ammonite which seems to be Am. [Lytoceras] Jukesi. Dr. Blackmore also states .that in 1893 a well was sunk on the Southampton road above Shootend arid a little beyond the second milestone from Salisbury ; it passed through ■— Ft. Clay and Sand - 12 Chalk of the Bel. mucronata zone - 63 and many fossils were obtained from the chalk which was brought up, including five examples of Bel. mucronata. Still further east, near Clarendon, there are some pits in this zone. One near the keeper's house in Clarendon woods is about 10 feet deep in soft white brittle chalk, with a few scattered flints, which often occur on one plane, but at distances of 2 or 3 feet from one another. The flints here differ from those at Shootend in having an ordinary white crust, but just the same assemblage of fossils is found. There is another pit in similar chalk near the Clarendon brickyard, and here the beds show a dip of 3° to the east. The fossils from the different zones of the Upper Chalk near Salisbury have been carefully collected and tabulated by Dr. H. P. Blackmore,* and the full list will be found in Mr. Jukes- Browne's Memoir on the Cretaceous Kocks of Britain, vol. ii. * Some Notes on the Aptychi from the Upper Cilalk. Geol Maa dec. 4, vol. iii, p. 529 (1896). "' EOCENE. . 61 CHAPTER IX. EOCENE. Eocene strata are only preserved in the south-east corner of our area. The main Tertiary escarpment enters the district' at the point where the Salisbury and Romsey roads fork ; ' but only enters it for half-a-mile. Eocene strata, however, are again brought in by a fairly deep synclinal fold, which runs through Alderbury and Grimstead. In this trough three divisions are preserved, and'we find Reading Beds, London Clay, and Bagshot Sand. A few miles further north, near 'Laverstock and Figsbur'y Ring, there are small outliers of Reading Beds. The total area of the. Eocene strata is, however, only about 7 square miles. BEADING BEDS. These apparently consist in the main of red-mottled clay above and of glauconitic sand or loam below. Their thickness isestimated by Mr. Bennett at 50 feet, which is somewhat less than is found in the Ringwood area, where they average 80 feet. No sections are now visible in the narrow outcrop around Alderbury ; but at the new house near the second milestone from Salisbury the drive was cut through these beds. At the house close to the junction with the London Clay, bores were put down 40 feet through mottled clay, and near the lodge green sand with a bed of pysters was met with. About 10 feet of this sand was passed through in sinking a well to the Chalk at the lodge belonging to the house close to the high-road. Only the lower strata come into our area in the outcrop near Brickworth House, and these consist of sand and pebbles, in which pits were formerly open. The small outlier near Laver- stock shows traces of red-mottled clay and a pebbly soil ; the outlier near Figsbury Ring shows many old holes in loam and pebbles. It will be noticed that besides the exposures mapped as Eocene, much of the "Clay with Flints" consists of Eocene material; it is still doubtful, however, to what extent this material represents outliers of Reading Beds in the immediate neighbourhood broken up and weathered without being trans- ported to any great distance. LONDON CLAY. The London Clay consists of grey or brown sandy clay, usually becoming more sandy and pebbly towards the base. It occupies an area of 4 or 5 square miles, and, according to Mr. Bennett, is probably about 150 thick,. The k>w§r 40 fe§t qf this deposit was 62 THE GEOLOGY OF SALISBURY. formerly well-exposed in the railway cutting through Clarendon Hill, north of Alderbury. Here Prestwich noted the following section : — a. Ochreous flint-gravel. b. London Clay ; dark bluish grey sandy clays with numerous PanopcBce, Ostrece, and Pinnae. c. Large tabular masses ; composed,- some of almost a pure green sand, and others of a coarse ochreous sand, with a calcareous cement. A few rather small round flint pebbles are scattered through these blocks. d. Alternating thin beds of sand and thick beds of mottled clay; chiefly red. " The chalk outcrops lower down the hill at a depth apparently of about 40 or 50 feet beneath ' c '."* This locality is celebrated for its fossils, which are in a better state of preservation than is usual in the London Clay. Mr. F. E. Edwards here made an extensive collection, and the list given below is compiled from the Catalogue of his collection, now in the British Museum (Natural History), the nomenclature there used being retained.f Only two sections are now open in which the London Clay can be seen, and in each case it is only the basement-bed that is worked. The Brickyard at West Grimstead shows 8 feet of sandy clay, dipping north. At the Clarendon Kiln 8 feet of brown clay is seen, and here also fossils have been met with. The fossils from Clarendon are mainly species known from the London Clay of other localities ; but among them are several species peculiar to this locality. As the list of mollusca is of exceptional interest, it is given here in full : — Bullinella uniplicata, Sow. Cancellaria [clarendonensis, Edw. cohsqrs, Desk. ■ MS.]. Scaphander parisiensis, Orb. Cancellaria teviuscula, J. Sow. Solidula simulata, Sol. [tenuiplica, Edw. MS.]. Actseon turgidus, Desk. Pyrula Smithii, Sow. Calyptrsea suessoniensis, Orb, [subcostellata, Edw. MS.]. aperta, Sol. Pisania curta, Sow. Sigaretus clathratus, Gmel. [cymatodiSj Edw. MSJ, Natica labellata, Lam — hantoniensis, Pilh. ■ epiglottina, Lam. granulosa, Edw. MS. J. Morrisii, Edw. MS.], transversaria, Edw. MS.]. Solarium pulchrum [var. primsevum, Trophon tuberosum, Sow. Edw. MS.]. . Typhis muticus, Sow. Solarium bistriatum, Desh. Murex plicatilis, Desk. Scalaria [Prestwichii, Edw. MS.]. Marginella gracilis, Edw. Cingulina Bourdoli, E. de Bov/ry. Voluta depressa, Lam. Turritella terebellata, Lam. elevata, Sow. Dixoni, Desh. muricina, Brug. Bayania [linigera, Edw. MS.]. tricorona, Sow. ; — _ n. sp. Pleurotoma acuminata, Sow. Cerithiella prselonga^ Desh. crassa, Edw. Eulima [similis, Edw. MS.]. pyrulata, Desh. Turbonilla sulcata, var. [clarendon- stena, Edw. ensis, Edw. MS.]. terebralis, var. pagoda, Edw. * Quart. Journ. Geol. Soc, vol. vi„ p, 257 (1850). t Systematic List of the F. E. Edward's Collection of British Oligocene and Eocene Mollusca, by R, B. Newton, 8vo. (1891)** EOCENE. 63 Pleurotoma terebralis, var. pulcher- Gari [clarendonensis, Edw. MS.]. rima, Edw. Tellina [clarendonensis, Edw. MS.]. Pleurotama terebralis, var. revoluta, Meretrix bellovacina, Desh. Edw. ■ obliqua, Desh. Pleurotoma teretrium, var. tubercu- orbicularis, Morris. lata, Edw. [ovum, Edw. MS.]. Pleurotoma gomphoidea, var. avita, suessoniensis, Watelet. Edw. Protocardiumfnitidulum, Edw.MS.]. Pleurotoma tereticosta, var. soror, subdiscors (1), Orb. Edw., Lucina [clarendonensis, Edw. MS.]. Pleurotoma turpis, Edw. Cardita Brongniarti, var. clarendon- Pleurotoma denticula, var. macrobia, ensis, S. V. Wood. Edw. Astarte clarendonensis, S. V. Wood. Pleurotoma Prestwichii, Edw. Nuculanapartim-striata, S. V. Wood. simillima, Edw. prisca, Desh. monerma, Edw. Nucula curvata, S. V. Wood. pupoides, Edw. Axinaea (Pectunculus) decussata, variata, Edw. Sow. Cassis substriata, Edw. MS. Area tumescens, S. V. Wood. Aporrhais Sowerbii, Mant. Modiola [clarendonensis, Edw. MS.]. Corbula costata, var. [clarendonensis, Pinna affinis, Sow. Edw. MS.]. Ostrea flabellula, var. modicella, S. Corbula [substriata, Edw. MS. J. V. Wood. [tenuisulcata, Edw. MS.]. Ostrea pulchra, Sow. Glycimeris intermedia, Sow. Anomia anomialis, Lorn. BAGSHOT SAND, The Bagshot Sand occurs as an outlier of about two square miles, extending from Alderbury to East Grimstead. It consists of false-bedded ferruginous sand, with lenticular masses of pipe-clay and with thin beds of ironstone. The thickness shown is about 50 feet, but this includes the lower part only of the formation, which reaches 200 feet in the district further south, where the whole is preserved. But few sections are now visible, the follow- ing notes giving the principal exposures. On the top of Alderbury Hill, at the point where the road to Ivychurch leaves the Southampton road, a pit shows five feet of ferruginous sand with some pipe-clay and ironstone. At the south end of the same hill a large pit shows about 30 feet of false- bedded ferruginous sand with pipe-clay in the upper part, the lower part being much obscured. At Whaddon, on the east side of the rail and close to the high road, a pit shows ten feet of brown sand, and this sand is also shown in the road cutting. Another pit, a quarter of a mile west of West Grimstead and close to the high-road, shows yellow and pinkish false-bedded sand with a lenticular layer of pipe-clay. The sections in the railway-cuttings are now all overgrown, as are several pits open at the time of the original one-inch survey. No fossils appear yet to have been found in the Bagshot Sand of our area, 64 THE GEOLOGY OF SALISBURY. CHAPTER X. DRIFT. No large area within the district dealt with in this Memoir is obscured by drift, and the drift that does occur is usually of no great thickness. The classification of the more ancient of these deposits is not altogether satisfactory, for the exact correlation of various outliers at different levels, having difterenTcooiposi- -tions, and yielding no fossils, is by no means easy. To what extent the Clay with Flints overlying the Chalk is equivalent to the more pebbly Plateau Gravel which rests on the Eocene strata, remains to be worked out. We will, however, deal with the de- posits according to their approximate date of formation.- CLAY WITH FLINTS. Over many of the higher ridges and plateaus formed by the flinty Upper Chalk there is spread a sheet, sometimes five or ten feet in thickness, of unworn or shattered flints in a black or red- dish clayey matrix. This deposit is unstratified, rests on a very irregular chalk-surface; and can often be traced to considerable ' depths as vertical cylindrical masses, which have sunk into pipes or pot-holes in the Chalk. The origin of the Clay with Flints has been much discussed, and is probably composite ; its age also is somewhat indefinite. Parts of the deposit are mainly composed of Eocene material, reconstructed almost in place, and dating from any period since the land last rose above the sea. Other parts are derived in large measure from the Chalk below, which has gradually been dis- solved, leaving an insoluble residue of unworn flints mixed with a little fine day ; this also may be of many different dates. Everywhere, however, there is a considerable admixture of material that cannot have been derived from the strata immedi- ately below. We find in it, for instance, chalk-flints belonging to zones which only outcrop some distance away on higher ground. It also contains pebbles derived from Tertiary deposits, which cannot have rested directly on the Chalk in that neighbourhood : on washing the matrix we obtain a sandy residue consisting of rounded grains of quartz such as could not have been derived from the Upper Chalk. Wind also seems to have played an im- portant part in transporting the fine dust which now helps to make the matrix of the Clay with Flints so clayey and impervious. Another thing must be taken into account in estimating the date of any particular part of the Clay with Flints. It is hio-hly probable that much of the deposit was to some extent disturbed and reconstructed during the Glacial period; when floods, caused by the melting of the snow or by rain falling on frozen soil combined with creep or soil-cap motion further- to mix material which had already been moved, DRIFT. 65 The distribution of the Clay with Flints is somewhat peculiar, and the reasons for its partial and irregular spread are not thoroughly understood. A glance at the Map will show that the chalk-plateaus over the southern half of our area are all capped with sheets of this deposit ; whilst in the northern half, including the very level plains around Stonehenge, it is too thin and irregular to be mapped, Chalk being usually so near the surface as to be turned up by the plough. PLATEAU GRAVEL. At levels high above the present Avon, scattered deposits of flint-gravel are to be found, and these seem to represent a very early and much-eroded Alluvial flat of that river. It is not easy to make out the relations of these various isolated patches of gravel around Salisbury, and for an account of the ancient valley of the Avon and of its deserted river-terraces, the reader must be referred to the Memoir on the country around Ring- wood. In that Memoir is described the lower Avon, with its wonderful series of ancient terraces, of which only mere traces extend into the .Salisbury area. Outliers of Plateau or High Terrace Gravel — for the gravel- covered plateaus, where well preserved, are seen to be merely parts of terraces bounded by still higher bluffs— have only been mapped in the' south-eastern part of our area, in the country immediately around Salisbury. Two of doubtful extent have been mapped by Mr. Bennett on the west of the Avon, opposite Old Sarum, at a height of 450 feet above the sea. These now show no section ; but the pebbly nature of the soil suggests that they may be reconstructed Eocene outliers. Ihe next outlier is one which caps Bishopsdown, a ridge lying between the Avon and the Bourne. This sheet occupies an isolated hill, rising to a height of over 300 feet above the sea, between Salisbury and Old Sarum. No section is visible ; but" Dr. H. P. Blackmore has here found rude flint-implements of "Eolithic" type. He has also found similar implements on Thorny Down (533 feet), Laverstock (486 feet), Burroughs Hill (319 feet) ; but, unfortunately, exposures are seldom visible in the higher outliers, and we cannot say to what extent implements found on or near the surface may belong to the gravel, or whether this gravel is truly of fluviatile origin. The outlier of Plateau Gravel at Alderbury lies at a height ol about 320 feet above the sea and nearly 200 feet above the gravel-flat of the river below. The best section is that seen in a large pit south-east of Ivychurch, where Mr. Bennett notes "12 to 15 feet of ferruginous gravel in a clayey matrix. The gravel is bleached in the upper part, and very ferruginous in the lower, and contains thin seams of sand and irregular beds of clay, brown at the top and grey and mottled below. Sometimes the clay occurs as a thin bed, at others as pipes up to eight feet deep, in the northern part of the pit the clay seems to end altogether." In this pit, Dr. H. P. Blackmore has found many rude eolithic 66 THE GEOLOGY OF SALISBURY. implements at all levels in the gravel.* Mr. Bennett observes that the gravel contains 4 per cent, of pebbles, 3 per cent, of chert and ironstone, and 1 per cent, of sarsen stone. The pebbles are derived from the Eocene strata, as is, perhaps, some of the chert ; but most of the Greensand chert, in all probability, comes direct from the Greensand of the Vale of Wardour. Two outliers of Plateau Gravel at a somewhat lower elevation will be found further to the east, near West Grimstead. The only remark that they call for is that, the material is more largely of local origin, the proportion of flint-pebbles rising to 15 to 25 per cent. When we return to the neighbourhood of the Avon and examine the gravel outliers at Standlynch, we notice that the proportion of flint-pebbles again falls and the proportion of Greensand chert from the Vale of Wardour becomes very large. It looks as if the gravels near the Avon were true Avon river- gravels, whilst those of Grimstead may belong to a small lateral tributary not crossing Greensand ; in these latter, chert seems to be very rare. Though no ancient river-gravels have been mapped at corres- ponding heights in the upper parts of the various valleys which combine at Salisbury, yet close search revealed numerous partially-worn fragments of flint and chert in fields 200 feet above the Nadder, near Tisbury. The exact locality is in the gap west of Lady Down, where the gravelly patches are found just north of Vicarage Barn (marked on the Map), and again a quarter of a mile north-west of the Tumulus. The outliers rest on Purbeck Beds at a height of 500 feet above the sea, and are now entirely cut off from the Greensand and Chalk by lower land; but the gap seems to correspond with an ancient north and south valley which runs up to Chilmark Down. The stones must have been transported at a time when the contour of the country was very different from that now seen; but nothing more definite can yet be said about them. Though the fields were searched for eolithic implements, I found none; but the locality is worth further examination. VALLEY GRAVEL AND BRICKEARTH. Between the Plateau or High Terrace Gravels and the series next to be described there occurs a local break of some importance ; though in adjoining districts the gap seems to be filled up. The valleys appear to have been deepened considerably during this interval, so that the highest of the more modern river-terraces in this area is sharply cut off from the terrace above. The lower terrace, however, is often composite and readily separable into an upper and a lower terrace a few feet apart : in fact, in the lower part of the Avon vallev, outside our area, the wide gravel flat is often seen to form several distinct steps. * See also Rev. R. A. Bullen, Eolithic Implements. Victoria Institute Trans 1901. DRIFT. 67 As these old fluviatile and subaerial deposits are well developed, in each of the valleys, it will, perhaps, be most convenient to com- mence our description with the central area around Salisbury. In this central area it happens also that the beds are fossiliferous, and in various ways noticeable ; only here, and at one spot in Devonshire, have fossils distinctly -characteristic of the Arctic regions yet been found near our south coast. Sheets of clean-washed river-gravel a few feet higher usually border the low modern flood-plains of the existing streams ; but above these, on the hill slopes in the immediate neighbourhood of Salisbury, occur alternating loams and. earthy gravels, which, though probably of very similar date, may be of quite different origin. The most noticeable of these deposits is that worked in the brick-pits of Fisherton, where it occupies the lower part of the spur which divides the Nadder from the Avon valley. Quite an extensive literature has grown up relating to the Fisherton pits and their fossils, for the bones of large mammals were noticed at a very early date, and it was not long before it was discovered that among the mammals were several that now characterise regions far colder than ours.* So much of the brick-earth has now been worked out, and so many of the sections are obscure, that it will be convenient to quote the account given by Prestwich, who wrote when the pits were in full work. His section of the strata in Harding's brick- yard, as exposed about the year 1854, is as follows : — Ft. a. Earth and flint-rubble, variable - - - 1 to 2 b. Eubble of angular flints, fragments cf chalk, and flint- pebbles, in clay and brick-earth - ■ 4- to c. Brick-earth, mixed with variable masses of flint and chalk- rubble, and containing bones and a few shells, chiefly in the lower part - 10 to 18 d. Light-coloured fine marl, full of well-preserved shells, with a few bones - - - - 1 to 2 e. Flint and chalk-rubble, with sand and clay, only upper surface exposed 3 to 4 (?) Chalk.. " The shells in the brick-earth, c, are here, as in the same drift in the other parts of the valley, few and irregularly dispersed ; but in the underlying marl, d, they occur in the greatest pro- fusion, in a very perfect state of preservation, and with traces of colour still discernible in some specimens It is, how- ever, in the brick-earth, c, that most of the bones are found. . .... The water-molluscs, with the exception of the Sue cinea putris, which is abundant . . . . , form a group such as we might expect to find in a spring or shallow pond rather than in a river." * Lyell, On Some Fossil Bones of the Elephant and other Animals, found near Salisbury, Proc. Oeol. Soc, vol. 1, p. 25 (1827); Prestwich and Brown, On a Fossiliferous Drift near Salisbury, Quart. Journ. Oeol. Soc, vol. xi, p. 101 (1855) ; Blaekmore. List of Mammalia from Fisherton, Geologist, vol. vi, p. 395 (1863) ; Evans, On Some Recent Discoveries of Flint Implements in Drift-deposits in Hants and Wilts, Quart. Journ. Oeol. Soc, vol. xx, p. 188 (1864) ; Blaekmore, in Stevens, Flint Chips, pp. 12—30 (1870) ; Evans, The Ancient Stone Implements, &c, of Great Britain, Ed. 2 (1897). 68 THE GEOLOGY OF SALISBURY. Since Prestwich made the foregoing observations, the mam- malian remains have been most carefully collected and deter- mined by Dr. H. P. Blackmore, of Salisbury, who has been so good as to provide us with the subjoined revised list of the species he has discovered : — Bos bison taurus, var. primigenius Cams lagopus - — lupus vulpes Cervus elaphus Elephas primigenius Equus caballus Felis leo Hyasna crocuta Lepus variabilis ? Microtus nivalis ratticeps Myodes torquatus Ovibos moschatus Rangif er tarandus Rhinoceros antiquitatis SpermopMlus erythrogenoides Nothing is yet known as to the plants which accompanied this Arctic fauna. The associated land and fresh-water mollusca call for no remark, they are all living British forms. With the mammals were found some bones and fragments of an egg of the wild goose -(Anser palustris), a bird whose nesting is now restricted to more northern climes. Several other sections of the brick-earth were formerly visible on the north side of the valley between Salisbury and Wilton, and descriptions of these will be found in the papers already referred to. It will be observed that wherever this brick-earth occurs it consists merely of masses of loam intercalated in the low. terrace-gravel, with which it is intimately connected. The main part of the brick-earth seems to have been a subaerial wash of loam and flints, derived from the Chalk and Eocene bluff above, and deposited at the foot of the slope. This view as to its mode of origin is borne out by the discovery of so many skeletons of lemming, coiled up as though they had been smothered while hibernating in burrows in this talus-slope. Scree-material of similar nature accumulates rapidly under Arctic conditions, where vegetation is scanty and the rocks are readily broken up by the frost. Such Arctic conditions must have held when this group of high northern mammals occupied the south of England. The gravels associated with the brick-earth are of wider extent, for they occupy much of the flat bottom of every valley of importance in the district. They also cover sloping terraces at considerable heights above the existing streams ; but it is often very difficult to say to what extent these terraces are of more ancient date, or merely consist of talus which happens to have lodged on gentle slopes above the main gravel flat. The highest of these terraces are found near Salisbury, where they have yielded a good many Palaeolithic implements, specimens ot which will he found in the Blackmore Museum, in Salisbury. Bones of large mammals are occasionally found. The distribution of the Valley Gravels is shown on the Map ■ their composition calls for little remark. They are usually made up in the main of broken or little-worn flints and chalk, around Salisbury mixed with a considerable proportion- of flint-pebbles and greywether blocks derived from the Eocene deposits. In the valley of the Nadder, and in that of the Avon below Salisbury DRIFT. 69 they also contain a noticeable admixture of Greensand chert and some Purbeck and Portland chert derived from the higher reaches of the Nadder. The material of these gravels is there- fore entirely of local origin, and derived from higher parts of the valleys in which it is now found. No trace of erratics has yet been met with in this area, and it seems probable that the peculiar far-transported blocks seen in the middle of Stonehenge were brought from low-lands, now destroyed by or sunk beneath the sea, lying off the present mouth of the Avon. An erratic-strewn plain only rising a few feet above the present sea level seems in quite recent geological times to have fringed our south coast, though now it is only to be seen on the lee side of the Isle of Wight, especially in the Selsey Peninsula ; whence P. J. Martin suggested that the igneous blocks in Stonehenge were derived.* That these erratics are not merely confined to the Sussex coast is proved by the abundance of similar far-transported blocks under the sea as far west as Tor Bay and the Eddystone. Three or four thousand years ago, which seems to be the approximate date of the erection of Stonehenge, a belt of flat land, like that of Selsey, probably existed under the lea of the Isle of Purbeck ; and over such a flat, blocks of rock, originally ,from Brittany, Cornwall, and the Channel Islands, might be collected and carried up the Avon on rafts. The larger stones used in the building of Stonehenge are grey wether sandstone, of local origin, and derived from Eocene strata, probably from the Reading Beds. ALLUVIUM. The Valley or Flood Gravel just described usually descends to the level of the_ Alluvium, into which it seems imperceptibly to merge. But this seeming transition in most cases is only appar- ent ; for the Gravel is discovered by boring to pass beneath the Alluvial flat, and to sink considerably below the level of the bottom of the existing river. When the flood-gravel was being laid down, the land stood at a level considerably higher than the present, so that the valley-bottom was cut below the depth to which any floods of the modern river can excavate. We do not yetknow the full depth of this ancient channel of the Avon near Salisbury ; but it may lie fully a hundred feet below the present valley-bottom. All that we can at present say is, that the Avon, like every river in England, once had a steeper fall in its lower reaches, so that it could cut a deeper channel. Later subsidence of the land, or rise of the sea-level, pounded back the water, turned the lower part of the valley into estuary and lake, which were afterwards silted up by more modern gravelly and muddy Alluvium. In the region that we are here dealing with, this silt- ing and levelling up is nearly complete ; in Christchurch Harbour part of the ancient submerged valley of the Avon is still not entirely obliterated. * Phil. Mag., ser. 4, vol. xiii, p. 34 (1857). A Bibliography of Stonehenge and Avebury has lately been prepared by Mr. W. J. Harrison, JXag. Wilts Arch. Soc, vol. xxxii. Reprinted 4to., Devizes, 1901. 70 THE GEOLOGY OF SALISBURY. Little is known about the thickness of the Alluvium, as we have no borings in the middle of the old channel. A boring put down by Sir Arthur Blomfield, in 1896, in the Cathedral Close, in order to ascertain the character of the foundations of Salisbury Cathedral, showed : — Ft In. Alluvial soil - 4 White clay [marl?] - 1 3 Gravel - 28 To Chalk - 33 3 This gravel is constantly full of water, which stood in the trial hole almost to the top of the Clay. The Avon being a fairly swift and clear salmon stream, its Alluvium is largely composed of flint-gravel, which cannot always be separated from the more ancient river-gravel. The modern gravel, however, is usually smaller, and the stones are more worn and weathered than in the older deposit, which often contains large unworn masses of flint and greywether, probably transported by river-ice during the Arctic winter. The whole of the alluvial flats have been trenched and turned into water-meadows, this irrigation extending as far up the slopes ays it is practicable to lead the water. Long-continued irrigation, and the occurrence everywhere of ancient mill-dams, have so altered the alluvial flat as to make it difficult to say what would be the character of the land under more natural conditions. Probably, however, the difference of water-level would not be freat, for the numerous snags and fallen trees must have indered the flow almost as much as do the mills, with their clean straight channels and mill-races. The water-meadows of the Avon do not. appear to yield such good grass as do the corresponding meadows of the more muday Stour. The water- meadows of the Nadder, which bring down a good deal of clay, have a stiffer soil. ECONOMIC GEOLOGY. 71 CHAPTER XI. ECONOMIC GEOLOGY. Building Materials. A considerable variety of building materials is used in the district; but the only building stones sent away are those from the Portland and Purbeck rocks of the Vale of Wardour. Brick is the building material over most of the area, the same parts showing also buildings of rough flint, or poor cottages of mud, or walls of sun-dried bricks made of a sort of concrete of flint and chalk. In the Vale of Wardour both stone and brick are used, many of the modern buildings being of brick, even where stone is close at hand. Perhaps the most convenient order of dealing with the building materials will be according to geological formations, for in this area the different strata yield stone of different character, and the geological and economic classifications happen nearly to coincide. Mr. H. B. Woodward thus describes the Portland and Purbeck building stones of the Vale of Wardour* : — " Tn the Vale of Wardour the Portland Beds, known as Wardour Stone or Tisbury Stone, are extensively quarried and mined for building stone near Tisbury, at Chilmark, Chicksgrove, and Wockley ; and formerly there were old quarries at Lower Lawn, to the north of Tisbury. " The lower beds of the Portland Stone are those chiefly worked as freestone — they consist generally of greenish sandy limestones or calcareous sandstones, which become- paler when dry. They are used not only for building purposes, but for troughs, tombstones, &c. The most extensive quarries with galleries are thosefinthe Chilmark ravine, where beds of variable character are present, passing from sandy and glauconitic lime- stones into calcareous sandstpne. Mr. Hudleston notices how full of quartz grains these beds are, but they appear to be cemented to a certain extent by opaline silica, f " The principal beds are, the Trough Bed, a sandy limestone about 2 ft. thick, considered the best weather-bed, and used for building stone steps, paviours, &c. ; the Green Bed, a sandy and glauconitic limestone sometimes shelly, and about 5 feet thick ; the Finney Bed, a sandy and glauconitic limestone, a good weather stone, about 2 feet thick ; and the Fretting Bed, a very sandy and partially calcareous rock, a little over 3 feet thick ; the thicknesses above given being those of the merchantable stone. " The Portland Stone of the Vale of Wardour was employed * The Jurassic Rooks of Britain, Vol. v. The Middle and Upper Oolitic Rocks .... pp. 312, 313, 317. Mem. Geol. Survey, 1895. + Proe. Geol. Assoc, vol. vii. p. 171. 72 THE GEOLOGY OF SALISBURY. in the Cathedrals of Salisbury, Rochester, and Chichester, in Wardour Castle, Longford Castle, F.onthill Abbey, Wilton Abbey Romsey Abbey, Westminster Abbey (Chapter House), Christ- church Priory, Balliol College at Oxford, &c. " An upper and oolitic freestone has been obtained by means of galleries at Chilmark; it was employed in the west front of Salisbury Cathedral, and has lately been again worked." The specific gravity of the Chilmark stone is 2-48 (about 155 lbs. per cubic foot). The Tisbury stone weighs 153 lbs. per cubic foot, and absorbs 8'6 of its bulk of water. Analysis of the "trough bed " Chilmark stone gives* : — Carbonate of lime -* 79'0 „ magnesia 3'7 Iron, Alumina 2'0 Silica - 10-4 Water and loss 4 "2 Bitumen trace 993 In the Vale of Wardour, especial! ? at ,Teffont Evias, the beds of hard smooth-grained Purbeck limestone are worked for building purposes, and other coarser beds are used for flagstone or rough tiles. The sandstone in the Upper Greensand has been described at p. 42. It was formerly much ,used locally, but is now seldom worked. It has been employed in the building of St. Mark's Church, Salisbury. Brick and tile-making depend so largely on the local demand that only some of the suitable clays have been worked.. The Lower and Middle Purbeck clays are stiff and marly; but the Upper Purbeck and Wealden beds contain loams suitable for brick-making. The mass of the Gault is stiff and suitable for tiles aad pipes ; its upper part is loamy and makes good bricks. In the Eocene strata stiff tile-clay -occurs in the Reading series, and the London Clay is loamy, especially towards the top. The Clay with Flints in other districts is used for brick-making, though the bricks are not very good ; here the deposit is placed incon- veniently for any market, and water is usually deficient on the hill-tops. The Valley Brick-earth in the neighbourhood of Salisbury has been extensively dug, and great part of it is now worked out or built over. Lime. As scarcely any of our area is distant a mile from limestone, lime can be procured without difficulty. The Purbeck Beds and Lower Chalk yield argillaceous limestones suitable for hydraulic lime; the Portland limestone and the Middle and Upper Chalk give ordinary lime. * Report with reference to the selection of atone for building the new Houses of Parliament, 1889. Analysis by Prof. Daniell, p. 30. ECONOMIC GEOLOGY. 73 Road Metal. Over the greater part of the area flints gathered from the fields or dug in the Valley Gravel or the Clay with Flints, are used for road-making. Greensand chert and the hard cherty Portland beds are, however, extensively used in the Vale of Wardour. Water Supply. Over most of the district water is obtained without difficulty from $ie Upper or Middle Chalk. This water is good, but some- what hard. The water from the Portland Beds is excessively hard, and owing to the fissured character of the rock, great care is needed to avoid surface contamination. The Purbeck Beds yield a little water of poor quality, and that found in the Wealden is also bad. A good supply, of excellent water is obtainable from the Upper Greensand, which often gives out copious springs at its junction with the Gault. Such springs will be noticed at Ansty and Swallowcliffe. A small amount of water- is obtained from the Bagshot Sands. The watej 1 ! found in the Valley Gravel is largely derived from filtration from the adjoining river or from the Chalk. This source of supply is not a very safe one, for the f ravel is very porous, and the gravel-flats are largely occupied by uildings and farms. 6152, INDEX. Actinocamax quadratus, 51, 52, 58, 59. Agriculture, 1, 2, 70. Alderbury, 1, 3, 49, 59, 61-63, 65. Alluvium, 69, 70. Alvediston, 44, 45, 47, 48. Amesbury, 1. Ammonites giganteus, 5-8. gigas, 5. mterruptus, 34, 35, 37, 38. mammtllatus, 32, 34-36. ■ rostratus, 37, 40, 41. splendens, 39. varians, 45-47. Analysis of malmstone, 39, 40 ; of phosphatic nodules, 39 ; of Port- land Stone, 72. Andrews, Eev. W. R., 8, 14, 16, 20, 22-28, 30-32, 38, 39, 52, 53. Ansty, 33, 42, 73. Aptychi, 59, 60. Archceonisms, 19, 20, 25. Arctic mammals, 67, 68. Area of the district,, 1. Ashley Hill, 59. Avon, gravels of the, 65^-70. Valley, 1, 51. Bacon Tier, 22. Bagshot Sands, 63, 73. Balliol College, 72. Barford, 48, 54, 55. Barrois, Prof. C, 51-55. Basingstoke, 49. Baverstock, 43, 44, 49. Beef, 16. Belemnitella mucronata, 51, 52, 59, 60. Benett, Miss E., 8, 10, 12. Bennett, F. J., 45, 47-49, 52-55, 61, 65, 66. Bishopsdown, 52, 58, 65. Blackmore, Dr. H. P., 51, 55, 56, 58- 60,65,67,68. Museum, 68. Blake, Prof. J. P., 8, 10, 14, 21. Blomfield, Sir A., 70. Blue Bock, 24. Bourne River, 65. Bower Chalk, 44, 47. Boyton, 49. Brickearth, 67, 68. Bricks, 71, 72. Brickworth House, 61. Bristow, H. W., 16, 22. Britford, 59, British Museum, 62, 63. Brittany, erratics from, 69. Broad Chalk, 45, 47, 48, 50, 55, 57. Brodie, Rev. P. B., 20, 25, 28. Brown, John (of Stanway), 67. Buckland, Rev. Dr. W., 16. Building-stones, 2, 9, 10, 12, 13, 21, 24, 25, 42, 71, 72. , Bullen, Rev. R. A., 66._ Burcombe, 55. Burroughs Hill, 65. Buxbury Hill, 45-47. Camp Down, 51, 56, 57, 59. Cardium dissimile, 7, 8. Carruthers, W., 18. Castle Ditches, 33. Catherine Ford, 25, 33. Catsbrain clays, 32. Cerithium portlandicum, 6, 8. Chalk, 45-60, 72, 73. Rock, 45, 48-55. , solution of, 64. water from the, 73. pit House, 48. Chalky Series in Portlands, 9 10, 12-14. Channel Islands, erratics from, 69. Charlton, 57. Chert, Greensand, 31, 33, 34, 37, 40, 42, 73. Portland, 5. Purbeck, 16. Chichester Cathedral, 72. Chicksgrove, 5, 10, 12, 21, 25, 29, 71. Chilmark, 4, 5, 9, 10, 14, 16, 21, 23, 39, 71, 72. Down, 66. Chloritic Marl, 44, 45. Christchurch Harbour, 69. Priory, 72. Cinder Bed, 20, 24, 25, 27. Clarendon, 60, 62, 63. Clay with Flints-, 61, 64, 65, 72, 73. Clearbury Hill, 57. Codford, 45, 52. Colloid silica, 37, 39, 40. Compton, 55. Down, 48. Wood, 33 Cone-in-cone, 16. Contejean, C, 17. Coombe Bissett, 48. Coquand, H., 17. Gorbula alata, 19 TNDEX. 75 Cornwall, erratics from, 69. Creep, 64. Croucheston, 47. Cycads, 17, 20, 21. Gypridea; 19, 20, 24. Cyprina Brongniarti, 5. - — elongata, 7, 8. Cypris purbeekensis-. 19, 20, 24. Cyrena-beds, 5, 10, 23. Cyrena media, 19. Cytherea rugosa, 5, 7, 8. Dallard's Farm, 25. Daniell, Prof. J. F., 72. Dashlet, 25. De la Beche, Sir H. T., 16. Deptford, 49. Devizes, 42. Dinton, 4, 25-30, 32, 33, 35, 37, 38, 42, 47, 49. Dip of the Strata, 2, 3. Dirt-beds, 18, 20-22. Disturbances, 2, 3, 30, 50, 61. Donhead, 5. Downs, The, 49. Downton, 50, 57, Drift, 64-70. Dust, 64. East Grimstead, 1, 3, 63. Harnham, 58, 59. Knoyle, 5. Ebbesborne Wake, 48. Ebble Valley, 47, 48, 57. Economic Geology, 71-73. Eddystone, 69. Edwards, F. E., 62, 63. Endogenites erosa, 30. Eocene, 61-64. Eolian deposits, 64. Eolithic implements, 65, 66. Erratics, 69. Estuarine conditions in the Portland Beds, 5. Evans, Sir J., 67. Exogyra conica, 41, 42.- brwntrutana, 7, 8. sinuaia, 31, 35. Figsbury Ring, 61. Fisher, Rev. O., 20, 25, 28. Fisherton, 58, 67, 68. Fitton, Dr. W. H., 12, 14, 16, 17, 21, 25, 31-33, 39, 42, 44. Flagstone, 24, 25. Flints, Chalk, 51- 60, 71, 73. Portland, 9, 14. Folds, 2, 3, 30, 50, 61. Folkestone, 37. Fonthill, 14, 32, 33, 72. Forbes, E., 17, 18. Formations, table of, 2. Fovant, 25, 33, 42, 44, 46, 55. Fretting Bed, 71. Gaize, 40, 42. Gault, 34-39, 42, 72, 73. Glacial Period, 64, 67-70. Godwin-Austen, R.A.C., 16-18. Green Bed, 9, 71. Greywethers, 69. Grimstead, 1, 3, 59, 61-63. Gypsum, 16, 17. Hampshire Basin, 2, 3, 50. Harding's Brickyard, 67, 68. Haredene Wood, 33. Harnham Hill, 52. Harrison, Prof. J. B., 39, 40. W. J., 69. Hazleton, 14. Heights, 1. ffemicidaris pv/rbechensis, 17. Highfield, 52. Holaster planus, 45, 50, 51, 54, 55. Homington, 48, 51, 55. Hoop Side, 48. Horns, 10, Huddleston, W. H., 5, 8, 10, 12-14, 16, 71. Insects, Purbeck, 18. Isastrcea oblonga, 6-8, 13, 14. Isle of Purbeck, 69. Wight, 69. Isopod limestone,. 25-27. Ivychurch, 63, 65. Jaccard, A., 17. Judd, Prof. J. W., 17. Jukes-Browne, A. J., 16, 20, 22, 25, 27, 28, 30-33, 35, 37, 38, 43-60. Kimeridge Clay, 4, 10. Knap Farm, 42. Knighton, 48. Farm, 47. Ladydown, 25, 66. Laverstock, 61, 65. Lemming, 68. "Lets," 12. "Lias," 23-25, 28. Lime, 72. Little Durnford, 56\ London Clay, 61-63, 72. Lonjgford Castle, 72. Loriol, P. de,*l7. Lower Cretaceous, 30-38. Greensand, 4, 31-36. Lawn; 71. Lowry's Chart, 18. Luciria portlandica, 7, 8. Lulworth, 22. Lydekker, R., 17. Lydite-pebbles, 14, 15, 33, 34, 37,38. Lyell, Sir C, 67. Malmstone, 39. Mammals, Purbeck, 18< 76 INDEX. Mammoth, 68. Mantell, Dr. G. A., 17. Marcou, J., 17. Marsupites, 51, 52, 58. Martin, P. J., 69. Mead End, 44, 47. Melamopsis harpaeformis, 19. Melbourn Rock, 45, 47-49. Mere, 50, 54. Meyer, C. J. A., 18. Micraster coranguimvm, 51, 53, 54, 56, 57. cortestudinarium, 51, 52, 54, 55. -prascursor, 51, 54, 56. Milford, 58, 59. Museum of Practical Geology, 22. Nadder Eiver, 1, 12, 25, 66. drift of the, 68-70. Netherhampton, 56, 57. Newton, R. B., 34, 35, 62, 63. Newtown, 13, 14. Norwich chalk, 59 Oakley, 22. Odstock, 57. Offaster pillida, 58, 59. Okeford Fitzpaine, 34, 35. Old Sarum, 56, 65. Oppel, Dr. A., 16. Ostrea distorta, 19, 20. vesiculosa, 40, 41, 42. Palaeolithic implements, 68. Palaeozoic rocks, 2. Pahtdina carinifera, 19. elongata, 19. Panthurst, 30, 33. Pavlow, Prof. A., 17. Pebbles in Gault, 15, 34, 37, 38 ; in Lower Greensand, 15, 33 ; in Port- land Beds, 14, 15. Pecten asper, 37, 40-42. IcmellosuSj 6, 8. Pema Mi/tiloides, 7, 8. Phosphatic nodules, 38, 39. Physa Brisiovii, 19. Pinney Bed, 9, 10, 71. Pitchpenny Clump, 47. Plateau Gravel, 64-66. Portland, Isle of, 22. Beds, 5-18, 22, 23, 73. Sands, 4, 6, 10. Stone, 2, 9, 10, 71, 72. Prescombe Farm, 48, 55. Prestwich, Sir J., 62, 07, 68. Punch Bowl, 55. Purbeck Beds, K5-30, 72, 73. Pyt House, 8. • Quarries, 2, 8-10, 12, 13, 21-25, 42, 71, 72. Quarry Copse, 12. Quidhampton, 56- Ragstone, 9, 10, 12, 14. Ramsay, Sir A. O, 16, 18. Reading Beds, 61, 72. Rhodes, J., 47. Ridge, 23, 32, 37, 39, 40, 42, 47, 49. Ringwood, 61, 65. Rivers of the district, 1. Roach, 6, 9, 10, 12, 13. Road Metal, 2, 42, 73. Rochester Cathedral, 72. Rock-salt, pseudomorphs of, 16, 23. Romsey Abbey, 72. St. Mark's Church, 72. Salisbury, 1 -3, 50-52, 56-60, 65-70, 72. Cathedral, 70, 72. Plain, 1, 49, 51, 56. Scenery, 1. Sedgwick, Prof. A., 16. Selbornian, 37-44. Selsey, 69. - Shaftesbury, 50. Sharman, &., 38. Sherrington, 49, 52. Shootend, 59, 60. Silica, colloid, 37, 39, 40. Soft Burr, 22. Soil-cap motion, 64. Soils, 1, 2. Sponges in the Portland Beds, 6, 10. Standlynch, 66. Stapleford, 52. Starr'd Agate, 13, 14. Steeple Langford, 52, 53. Stevens, E. T., 67. Stone, building, 2, 9, 10, 12, 13, 71, 72. Stonehenge, 1, 2, 65, 69. Stour, River, 70. Strahan, A., 17, 23, 26. Stratford, 56. Strike of the beds, 2. Struckmann, Dr. p., 17. Structure, geological, 2, 3. Sutton MandeviTle, 30, 33, 39, 42. Row, 30, 33. Swallowcliffe, 33, 42, 73. Swallow-holes, 29. Swanage, 25. Synclines, 49, 50, 61. Teall, J. J. H., 16. Teffont, 4, 9, 10, 23-25, 28, 30-32, 42 72. Terrace gravels, 65-68. Tertiary deposits, 61-64. Test, River, 3. Thorny Bushes, 59. Down, 65. Tile-clays, 72. Tilestones, 25. Tisbury, 1, 4, 5, 9, 13, 14, 22, 23, 33, 66. star-coral, 6-8, 13, 14. Stone, 71, 72. Tor Bay, 69, INDEX. 77 Totterdaie, 33, 34. Trigonia. densinoda, 25. gibbosa, 7, 8, 10. Trough Bed, 9, 71. Ufford, 57. Unconformity at the base of the Lower Greensand, 29-36 ; between Purbeck and Portland Beds, 13, 16, 22 : in Portland Beds, 10. Unio mlderms, 19. Upper Greensan'd, 37, 39-44, 72, 73. Holt, 42. . Upton Lovell, 52. Vale of Wardour, 1-50, 55, 66, 71, 72. Valley Gravel, 66-69. Vectian, 31, 32. Vicarage Barn, 66. Wallmead, 4, 33. Wardour Castle, 72. Park, 34. Stone, 71. Warminster, 40. Water-meadows, 70. Water Supply, 73. Wealden, 4, 20, 25-33, 72, 73. Webster, T., 16, 17. West Grimstead, 59, 62, 63, 66. Harnham, 58, 59. Westlake, E., 56. Westminster Abbey, 72. Whaddon, 59, 63. Whitaker, W., 32. White Bed, 9, 24. White Sheet Hill, 1, 50. Wilton, 1, 56, 68. Abbey, 72. Winchester, 49. Wishford, 52, 53. Witherington, 57. Wockley„12, 21, 22, 71. Woodford, 53, 54, 56. Woodward, Dr. A. S., 17. H. 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