252 



THE GEOLOGIST. 



where it is largely developed. Several sections are well exposed at 

 the quarries near the Witney Cemetery, where its upper portion con- 

 sists of a dark- coloured bed of clay containing Bliyiichonella concimm, 

 Terehratula digona, and T. maxiUata, with spines of Cidaris, and 

 joints of Pentacrinites. This clay is divided about the centre by a 

 thin band of slaty sandstone, which, although not equal to the 

 Stonesfield Slate for the purpose, is capable of being worked by the 

 hammer into a rough kind of rooting- tile. This Forest Marble slate 

 recalls vividly to the mind the condition of the ancient Oolitic sea 

 by whose agency it was formed, the surfaces of many of its slabs 

 being strongly ripple-marked, and covered with the valves of small 

 Ostrese, Rhynchonellse, and comminuted fragments of other shells, 

 with here and there a perfect specimen of Pecten lens, or P. vagcms, 

 and occasionally a small sea-urchin, Diadema depressa. In one 

 solitary instance the writer was so fortunate as to obtain from one 

 of these slabs a specimen of Acrosalenia, much compressed, but still 

 retaining its long, smooth, pointed spines attached to their sockets, a 

 condition in which Echini are very rarely met with in this or any 

 other formation. These beds of clay and slate are succeeded by a 

 thick stratum of coarse shelly limestone, containing portions of coni- 

 ferous drift-wood, and but few organic remains of any kind, with the 

 exception of Lima cardiiformis and imperfect Terebratulas. At 

 Stonesfield the Bath Oolite consists of a soft white limestone, suc- 

 ceeded by a stratum of hard compact fissile ragstone passing down- 

 ward into the true Stonesfield Slate. The upper portion is very 

 fossiliferous, and contains several forms of life which seldom occur 

 in the lower division. These are chiefly some interesting corals 

 Thamnastrcea Lyellii, two species of Isastrcea, and some others, asso- 

 ciated with a flat species of sea-urchin, Glijpeus Midlerii, and much 

 more rarely a beautiful Hemicidaris as yet unnamed. This bed also 

 contains a variety of shells, among which may be enumerated Astarte 

 elegans, Terehratula maxiUata, Nerincea Pjudesii, N. melanoiS.es, Lima 

 cardiiformis, and a species of Chemnitzia, G. Hamjjtonensis. 



This division of the Bath Oolite may also be studied at Witney, 

 where it has yielded some interesting fish remains identical with 

 those of the Stonesfield Slate. At Minster Lovel, and other places 

 situated on the Cheltenham road, many cuttings have been made in 

 this formation, chiefly for the purpose of procming road-stone, for 

 which it is, however, but ill adapted, A quarry situated by the road 

 side, near the Minster turnpike, has furnished some instructive speci- 

 mens, chiefly the palatal teeth of fishes, with frag-nients of bone and 

 scales ; these are found in an insulated condition, and are confined to 

 a thin stratum of brown friable marl, forming the summit of the 

 section. 



The second division of the Bath Oolite, both in lithological compo- 

 sition and organic remains, is so nearly allied to the underlpng slate 

 that we shall prefer studying them in connection with each other, and 

 regard them both as belonging to one and the same period, rather 

 than treat of them as two separate and distinct formations. A com- 



