Clifton College Scientific Society. 51 



11. Black shales, ..... 



12. Gray argillaceous limestone beds, fish scales, 



13. Black shale in laminae, 



14. Thin calcareous and arenaceous bed, containing 



saurian remains and fish scales, 



15. Black shale in lamina3, ... 



16. The cebebrated bone bed, commonly a conglo- 



merate, composed of rounded portions of an 

 argillaceous and calcareous rock, mingled 

 with saurian and fish remains and coprolites, 

 varies from 1 to 8 inches. 



17. Pale arenaceous marls, with nodules of sand- 



stone, calcareous cement, generally changes 



to an arenaceous marlstone, . . .10 



18. Greenish marls, with small nodular fracture, 



varying in the lower part to sandy shales, . 2 



19. Marly sandstone, partly calcareous cement, . 6 



20. Arenaceous marlstone, nodular, greenish gray, 



and blue, . . . . .GO 



21. Bed marls, with stripes, and nodules of greenish 



blue, . . . . . 15 9 



22. Red marls, . . . . . 50 



23. Gypsiferous beds, gypsum in beds and strings, . 26 

 24<. Ked marls, somewhat sandy at the base, where 



they rest upon the upturned carboniferous 

 limestone, . . . . . 21 



These beds have been the subject of much controversy. The 

 upper beds, including the bone bed, were formerly regarded as 

 liassic, but they are now generally considered triassic. From 

 the fact of their corresponding to some beds in the Ehsetic Alps 

 they are called the Rhgetic beds. Another name for them is the 

 Penarth beds, because they are well shown at Penarth in Glamor- 

 ganshire. 



They may be divided as follows : — 

 Nos. 1 to 10. White lias. Fossils— Ostrea liassica, &c. No 

 ammonites or belemnites, which occur in profusion in the 

 lias. 

 Nos. 10 to 16. Black paper-shales, including the bone bed. Fossils 

 — Avicula contorta, Cardium rhseticum, Pecten valonensis, many 

 scales, teeth, bones, and coprolites of fish and saurians. 

 Nos. 17 to 20. Grey or greenish marls, not fossiliferous, and pass- 

 ing gradually into the variegated red marls of the keuper or 

 upper division of the trias. 



