988 Dr. FiTTON on the Strata below the Chalk. 



at Wockley in the Vale of Wardour, 5. b., p. 252., and at Garsington, 3. c, p. 277. ; 

 with Potamides carinatus ?. 

 \_Portland.'\ 



9, "Bottom Rock". This, in one of these pits, is an agglomerate of fragments of shells; 

 of a dark bluish hue, specked with white. In an adjacent pit it abounds in Trigoniee 

 and other Portland fossils. — Thickness not ascertained. 



The beds below are not visible, and are unknown to the workmen. 



The upper part of several other pits near Bishopstone (as at Southwarp and the vicinity of 

 Dinton,) agrees with the foregoing list, in exhibiting an alternation of clay, more or less like Fuller's 

 earth, with ochre and ferruginous sand : and the very dark clay which includes iridescent Mytili, 

 occurs in so many places that there can be little doubt of its former continuity tiiroughout this 

 part of the country. It is particularly distinct on the side of the road from Whitchurch to 

 Winslow, near the turn towards Dunton, about eight miles from Bishopstone ; where, besides 

 the usual Mytilus, it contains a Natica and another spiral univalve (Melanopsis ?). Beneath 

 these clays and sands is, universally, thin slaty marl or limestone, with alternate thin beds of clay, 

 containing everywhere the same fossils ; — Cypris, Modiolas, and spiral univalves, — among which 

 are Paludinae, a Planorbis, and perhaps some other species. The whole group, therefore, clearly 

 represents the strata above the Portland stone at Garsington, and in the Vale of Wardour ; and 

 is, no doubt, the equivalent of the " Slate", the " Cap", the " Dirt", and the other lower beds 

 of the Purbeck formation, on the Dorsetshire coast. 



Pit near Whitchurch : — A. {Denchjield's.) 



(Compare with the Section at Quainton, p. 289 — 290.) 



Ft. In. 



1 . Grass, over vegetable soil about 4 



[Lower green-sand and WealdenJ] 



2. Greenish white, coarse, sandy clay ; including rounded pieces of sandy stone 7 



3. a. Tough, grey, and greenish clay ; including b about 9 



b. A dark band of very tough clay about 6 



c. Clay, like a. ; the lower surface waved and irregular. This, at its June- "1 

 tion with the darker clay above, and for a short distance below, is full of I » 

 a thin iridescent Mytilus, so fragile that I could obtain only very imperfect [ 

 specimens J 2 



4. A group, which my guide called " Cornstonel". 



a. Grey and greenish sand, irregular in thickness 4 in. to 9 



b. Whitish clay, sand, and soft stone 1 5 



c. Tough, grey, and brownish clay, passing into d 5 



d. Similar clay, including concretions of gritty stone about 1 3 6 



5. " Green-stone", (so called), comprising, — 



a. A thin bed of hard, brownish clay, like part of 3. above 1 in. to 2 



b. Fissile sandy clay, greenish grey 4 in. to 5 



c. Hard calciferous gritty stone, in irregular concretions 4 



d. A band of yellowish grey soft sandy clay or marl about 1 o 



The calciferous grit, 5. c., which is like that of Bishopstone (5. p. 287.), and of Quainton 



(9. p. 290.), deserves notice, from its resemblance to the grit of the Hastings sands : and it 

 contains at Quainton casts of a spiral univalve, — Paludina (or Natica?). 



