FOSSIL MOLLUSCA— BIVALVES AND UNIVALVES. 249 



see them ornamenting the window-sills of the cottages, 

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

 dens. Etwmphahis pentangulattis is another abundant 

 Carboniferous univalve, and one of the most beautiful. 



Fig. nyi.—AntJir,' .,/«. 



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. Capiihis or Calyptrea, Naticopsis, 

 Miirchisonia, Solarium^ Nerita, Posidonomya^ Safi- 

 guinolites, Pinna^ Pecten^ Cardiomorpha, etc., are not 

 unfrequent. In the black Carboniferous limestone 



Fig. 233. — Pleiiroioiimria 



cafinata (Carboniferous 



limestone). 



