FOSSIL MOLL USC A BIVALVES AND UNIVALVES. 249 



see them ornamenting the window-sills of the cottages, 

 or conspicuously placed in the " rockeries " of the gar- 

 dens. Euomphalus pentangulatus is another abundant 

 Carboniferous univalve, and one of the most beautiful. 



Fig. 232. Antkracosia robasta. 



It is very easily hammered out of the rock, where its 

 hollow coil leaves a pretty impression. At Castleton 

 it is extremely abundant, and may be met with in every 

 stage of development ; but, in point of fact, it is one 

 of the most abundant and cha- 

 racteristic of the Carboniferous 

 limestone fossils. Pleurotomaria 

 carinata is abundant in places, 

 as at Castleton one of the best 

 localities in Great Britain for 

 the exquisite state in which the 

 fossils are preserved. I have met 

 with Pleurotomaria there with the zigzag markings 

 still quite distinct. Capulus or Calyptrea, Naticopsis, 

 Murchisonia, Solarium, Nerita, Posidonomya, San- 

 guiiiolites, Pinna, Pecten, Cardiomorpha, etc., are not 

 unfrequent. In the black Carboniferous limestone 



Fig. 233. Pleurotomaria 



carinata (Carboniferous 



limestone). 



