Part of Gloucestershire and Somersetshire. .351 



terebratulites, Spirifer Walcotti (Sowerbj/), ostracites, gryphites, pectinites, 

 pinnites, modiolites, tellinites^ venuliteSj plagiostomites, a species of Astarte, 

 Hippopodium ponderosum {Sowerhy) ; of echinites, the spines and fragments 

 of the body ; and of the crinoidal family , pentacrinites. Stems and branches 

 of wood hkevvise occur, both half decayed and in the state of coal, firmly encased 

 in the solid lias limestone. In the collection of Dr. Cooke are vertebrae, bones, 

 and palates of fish, and radii of balistae ; also crastacea bearing some resem- 

 blance to prawns and shrimps ; — most of them obtained from the ossiferous 

 beds of the lias formation at VVestbury and Aust cliffs, — in which also occur, 

 adjacent to the new red clay marl, bones and vertebrae of the plesiosaurus ; 

 while at Pyrton, the remains of the ichthyosaurus are found in the blue marl 

 and clay above the lias limestone. Several of the above-mentioned organic 

 remains are met with also in the lias of Eastwood and Whitecliff-park ridges, 

 in that adjacent to the right bank of the Avon, and in the outlying portions 

 of lias at Tortworth. 



§ 30. I am not aware that a continuous section from the lias to the oolitic 

 beds is any where distinctly displayed within this district; and the portion of the 

 oolitic series which appears in the great escarpment, that bounds the vale of 

 the Severn on the east, belongs to that division which has been distinguished 

 as the lower oolite by Professor Buckland, and by Messrs. Conybeare and 

 Phillips. The following appears to be the general arrangement of the beds 

 in the environs of Tortworth : — 

 At bottom, 



1. The lias limestone. 



2. Lias clay and marl. 

 Above these, 



3. Brown marl alternating with beds of marly sandstone. 



4. Ferruginous sand, containing balls of sandstone, composed of concentric 



layers, surrounding calcareous nuclei. In the upper strata of this bed, 

 thin layers of oolite occur. 



5. Inferior oolite ; traversed by fissures of variable width, the walls of which 



are frequently coated with rock-milk (Chaux carbonatee spongieuse of 



Haul/), or with stalactite. The lower strata of this oolite often contain 



small tubular or cylindrical channels, closed at both extremities. 



The preceding beds constitute what may be termed the exterior terraces of 



the escarpment, and are succeeded higher up in the interior by the Fuller's 



earth and great oolite. 



An outlier of the bed No. 3. occurs also in the southern end of Whitecliff- 

 park ridge, on the top of the hill, above Hill court, appearing there as a thin 

 VOL. VI. 2 z 



