PLATE XXXI. 



CARBONIFEROUS SPECIES. 



Fig. 

 1 . Productus sub-laevis, Be Koninck. Stated to be from the Carboniferous lime- 



stone near Leek, in Staffordshire (but 

 probably from Clitheroe, in Lancashire). 

 Coll. of Dr. Bowerbank. 



-• » » From the Carboniferous limestone of Llangollen. Museum 



of Practical Geology, London. 



3. „ plicatilis, Sow. From the limestone of Longnor, Derbyshire. 



Museum of Practical Geology. 



4. ,, „ From the limestone of Settle, in Yorkshire. 



5- „ „ Internal cast of the ventral valve, from Longnor, in 



Derbyshire, showing the position of the adductor and 

 divaricator muscular impressions. 



6- „ mesolobus, Phillips. A remarkably circular example from the 



Carboniferous limestone of Settle, in 

 Yorkshire. 



7, 8. „ „ Two specimens of the more common shape, from 



Yorkshire. 



y - v => From the Glarat limestone, Campsie, Stirlingshire, 



Scotland. 



