SECTION XII. 



247 



The chief kinds of foflil Efcallops yet 

 undifcovered, recent or living from fea, are 

 as follow. 



Firft. Size of the common Oyfter, with 

 large but unequal ears, of a perfeftly round 

 contour ; the ilirface tranfverfly thick fet 

 with prominent fharp thin ridges, like 

 plates. The valves are equal. Thefe are 

 found very fi'equently in the quarries at 

 Thame in Oxfordfhire. 



A fecondkind very elegant, about double 

 the fize of a Cockle, the valves unequal, 

 one being quite flat, th6 other exceeding 

 concave. It is thickly ridged length-w^ays 

 with many common ridges and interme- 

 diate ones, that arc very prominent or 

 high, and the furrows are broad and deep. 

 It is found in the quarries of Dorfetlhire, 

 Wiltlhire, and the adjacent counties, as 

 alfo fometimes in the chalk-pits of Kent 

 aud Surrey. 



R 4 Thq 



