﻿PLATE XX. 



I, 2. Rhynchonella acuminata, Martin, sp. Typical shape. Carboniferous limestone, 



Clitheroe, Lancashire. Gilbertsonian Collection. 

 British Museum. 



3. — — From the Isle of Man, and collection of the Rev. J. 



G. Cumming. 



4. — — From Park Hill, Longnor, Derbyshire, and collection 



of the School of Mines. 



5. 7, 8. — — From Settle, in Yorkshire. Collection of Mr. 



Burrow. 



6. — — Interior of the dorsal valve. 



9, 10. — — Isle of Man. Collection of the Rev. J. G. 



Cumming. 



II. — — From Yorkshire. Collection of Mr. E. Wood. 



13. — — From Kildare, in the collection of Professor 



Phillips. 



