16 



THE LIAS AMMONITES. 



Section of the Zone of Aegoceras planorbis, at Street, Somerset. 



No. 



LlTHOLOGY AND LiOCAL NAMES OF BEDS. 



Light-coloured marly clay. " Top Bed " 



Light-coloured Lias limestone 



Yellowish laminated shale, splitting up 



into thin layers 



Light-coloured shaly limestone 



Hard grey limestone. " Building-stone " 



Dark-grey shale 



10 

 11 



12 

 13 



14 



15 



16 



17 



18 

 19 



20 

 21 



22 

 23 



24 



25 



26 



Dark-grey limestone. "Corn-sized build- 

 ing-stone" 



Ostrea Series. 



Dark laminated shale 



Dark-grey limestone. " Five-inch build- 

 ing-stone " 



Dark shale 



Dark-grey limestone. " Six-inch build- 

 ing stone" 



Dark shale 



Greyish hard limestone. "The Whet- 

 stones." Best paving-bed. Consisting 

 of two 4-inch beds 



Hard dark marl. " Saurian bed" 



Greyish fine-grained limestone. " The 

 Cream-bed." Fine-grained paving- 

 stone 



Brownish limestone. " Red Liver." 

 Paving-stone 



Dark-coloured limestone. " The Black 

 stone," used for large paving-slabs ; 

 some of them 10 ft. by 5 ft 



Dark-blue shale 



Hard greyish limestone. " Six-inch 

 building-stone " 



Soft bluish shale 



Greyish-blue limestone. " Four-inch 

 building-stone" 



Dark-gray laminated shale 



Hard blue limestone. "The Blue Clog," 

 or " One-foot building-stone," used 

 for steps 



Grey laminated shale 



Thick- 

 ness. 



ft. in. 



3 



9 



3 



4 



7 



3 



6 



4 



Organic Remains. 



Planorbis Series. 

 Saurian bones and Aegoceras planorbis. 

 Aegoceras planorbis in moulds. 

 Ichthyosaurus intermedius, Aegoceras planorbis, 



Lima punctata, and Isastrcea Murchisoni. 

 Aegoceras planorbis, compressed. 

 Aegoceras planorbis, on the top of the bed, Lima 



punctata and Lima gigantea. 

 Aegoceras planorbis and muricated spines of 



Cidaris Edwardsi. 

 Spines of Cidaris and bones of Ichthyosaurus 



tenuirostris. 



Ostrea Series. 



Ostrea liassica. 



Greyiah limestone. "Grey Clog." A 

 valuable building-stone, used for steps, 

 troughs, &c 



Dark shale 





 



8 

 9 







3 







4 





 



4 



2 





 



6 



2 





 



4 

 4 



1 



1 





 3 



1 











2 



Ostrea liassica. 

 Ostrea liassica. 



Cardinia crassiuscula, Lima punctata, and Ostrea 

 liassica. 



Fossils rare : Ostrea liassica and Modiola minima. 



Many Saurians have been obtained from this bed. 

 Ichthyosaurus intermedius and Plesiosaurus 

 Hawkinsii (British Museum). Many jaws of 

 Saurians and Fishes. 



Ostrea liassica and Modiola minima. 



Few fossils. 



Modiola minima, Ostrea liassica, Pleuromya, and 



Rhynchonella variabilis. 

 Ostrea liassica and Modiola minima. 



Ceromya, sp., Modiola minima, and Ostrea liassica. 



Fossils as in No. 19. 



Ichthyosaurus intermedius and I. tenuirostris. 



Ceromya, sp., Ostrea, Modiola, and Rhynchonella. 

 Saurians abundant : Ichthyosaurus intermedius 



and I. tenuirostris, Pholidophorus leptocephalus, 



Agass. 



Modiola minima. 



