266 OUR COMMON BRITISH FOSSILS. 



the glaring whiteness of the chalk quarries in the hot 

 summer sunshine, as they will be in later life. In 

 Kent, Sussex, Dorset, Suffolk, Norfolk, Lincolnshire, 

 Hertfordshire, etc., as well as the North of Ireland, 

 every Chalk-pit contains fossils, more or less. True, 

 both bivalves and univalves are comparatively rare, 

 for these indicate that the strata they are found in 

 were deposited in shallow water, whereas all the 

 fossils incident in the Chalk, and especially in the 

 Upper Chalk, bespeak deep water. Perhaps the earlier 



Fig. 245. — Pectcn orbicularis (Chalk). 



geologists thought the White Chalk was originally 

 formed in deeper water than it is now known to have 

 been ; but it must still be regarded as a deep-sea 

 deposit, in comparison with the varying strata of 

 the Oolite. 



The Lower White Chalk, perhaps, contains more 

 fossil bivalves than the Upper. Some of them attain a 

 large size, such as Inoceramus Cuvieri and Inoceramus 

 Lamar cki, whose vertically fibrous structure reveals 

 to the student the presence of the smallest fragment. 



