452 T. R. JONES AND C. C. KING ON SOME 



other Bivalves, also many Sharks' teeth, not of large size, and one 

 fragment of a palate of Myliobates (Wheeler's pit). Carbonized 

 woody matter was also observed in small quantities. Besides the 

 green-stained unworn Chalk-flints characterizing this deposit, pebbles 

 also of flint occur, and many sharp fragments of flint, which have 

 nothing but the glaze of their surface and their position in the series 

 to indicate antiquity. Possibly they were split off on shore by frost 

 in cold seasons of the period. One small pebble of siliceous schist, 

 another of quartzite, and small angular pieces of Chalk were also 

 met with. 



At one spot in the northern pit of Coley Hill Oyster-shells were 

 absent ; at all events, in the small area (about 4 feet square) of the 

 trial-pit, shown by the lower part of Section No. 3 (PI .XXII., plan 

 of the pit, figs. 3 & 4). In the adjacent large Chalk-pit (Section 

 No. 4, fig. 4), 35 yards to the east, there was clear evidence of the 

 Oyster-bed, and indeed of its forming two layers. 



In Mr. Wheeler's pit (marked " Coley Kiln " on the Ordnance 

 Map) on the southern side of the hill, about 120 yards distant, the 

 Oysters abound at the same horizon, but are not distinctly in two 

 layers. 



The Ostrece are known to occur at Katesgrove, -J- mile to the east, 

 and at the railway-cutting, j mile to the west, near the Bath Road ; 

 but they were not found by Mr. Whitaker at Castle Kiln, about 200 

 yards to the north (< Mem. Geol. Survey, Explan. Sheet 13,' pp. 24 

 and 39). 



§ III. The Blue Clays in the Buff Sand. — As elsewhere, in neigh- 

 bouring sections described by Prestwich and Whitaker, a blue shale 

 occurs in Section No. 4, at about 12 feet above the Chalk. We re- 

 cognized it at Collier's, Wheeler's, and Poulton's (Katesgrove) Pits as 

 a laminated, tough, silty clay, with frequent patches of decomposed 

 vegetable matter, and with black (manganese ?) infiltrations in its 

 jointings. 



In Section No. 4 a seam of lignitiferous bluish grey clay, 3 inches 

 thick, traverses the yellow sand 3 feet 6 inches above the bluish 

 shale above mentioned ; and in Wheeler's pit, 118 yards distant, on 

 the south side of the hill, there are three or more similar seams, 

 curved, and varying in thickness and persistency, in a corresponding 

 position among the false-bedded yellowish sands. 



In Section No. 4 the lower band of shale has a full development 

 of about 3 feet, with yellowish sand above and below; but at a 

 distance of 35 yards to the W., and verti&ally above the spot where 

 we noticed the absence of Oysters in the lowest beds, both this clay 

 and the upper and thinner seam* are wanting, yellow sands, 26 feet 

 thick, intervening between the " Bottom Bed " and the Mottled Clay 



* The leaf -bed, with which these blue shales correspond, has been found close 

 by, on the north, at Castle Kiln (Whitaker, ' Geol. Surv. Mem.' vol. iv. p. 197), 

 and half a mile to the west, at the railway-cutting near the Bath Road (Prest- 

 wich, Quart. Journ. Geol. Soc. vol. x. p. 88). It is also known to occur at 

 Shaw Hill, near Newbury, 13 miles distant. Mr. Eickman found that some of 

 the "Woolwich Beds" near Dulwich abound with leaves (Mem. Geol. Surv. 

 vol. iv. p. 131). 



