202 



peoceedinctS of the geological society. 



[Jan. S, 



The shells have disappeared, leaving very perfect casts. Under these 

 is the 



8. Avicula-led. — This remarkable deposit forms the bottom of 

 the quarry ; for the workmen do not find it pay to go lower, on 

 account of the expense of blasting the limestone-bed beneath. 



Fig. 3. — Montj^elier Quarry. 



ft. in. 

 >■ 11 -i Shales, clays, and lime- Fish-scales, Lima giyan- 

 stone (9 beds). tea, A,n. torus. 



Xo. 6. 



\^^^ 



r^^ 3 Clays and limestones 

 (i beds). 



Fish-srales abundant. 





Sandy clay Jaws and spines of 



Echini very plent'ful, 

 and also Cytheridce. 



► 17 2 Shaly bt-ds, &c (29 beds). A.Johnsloni, A. toHilii. 



Xo. S. 



4 Hardened clay. 



Avieula ci/gnipes. Sau- 

 rians, Ostrece, Peoten, 

 spines, &c. 



When well exposed, this bed is very interesting to the palaeon- 

 tologist. Specimens of the fme Avicida cygnipes, with the shell pre- 

 served, lie about in every direction, sometimes 12 or 14 in a square 

 yard, intermingled with saurian vertebrae, Ostrece,Pecten,2iiidL. Echinvjs- 

 spines ; indeed the bed is made up entirely of animal remains. 



It is, however, the succeeding beds which the author hopes may 

 help to settle the position of the Bridgend series. 



They present very decided evidence in favour of Mr. Bristow's 

 opinion of its being far above the Rhaetic beds, and in the Planorbis- 

 zone. 



From the following section it will be seen that the typical Pla- 

 norbis-fossils occur both above and below the Sutton fossils ; and both 

 are four feet above the well-known Gotham marble, which in the 

 Bristjol district is always known to be immediately above the Avi- 

 cula-contorta series. 



Unless, with Mx. Moore, we include the White Lias with the Ehaetic 



