Middle Oolites, Oxford Clay. 183 



than there is between those of what are called different 

 zones in other recognised single formations. 



Facts of this broad kind are of more importance to 

 the general reader than trying to remember names of 

 fossils, and what I now endeavour to do, is to disabuse the 

 mind of the idea, too often implied in manuals, that 

 the marked characteristic of strata is, that they consist 

 of perfectly distinct zones, each having its own species, 

 which have little connection with each other. What 

 applies to the Lias and Lower Oolites, equally applies to 

 the connection of the latter with the Middle, and of the 

 Middle with the Upper Oolites, and I shall therefore 

 treat the remainder of this subject as briefly as 

 possible. 



The next group of strata, as generally received, is 

 formed of the Middle Oolites, which consist or* the 

 following divisions, the oldest being placed at the 

 bottom : 



Coral Rag and Calcareous Grit. 



fClay. 

 Oxford Clay< Kelloway Rock. 



I Clay ; a thin band. 



In the south of England, much faulted, the OXFORD 

 CLAY occupies considerable strips of country between 

 Weymouth Bay and the river Bredy, about a mile east of 

 Burton Bradstock. Beyond that faulted region, and 

 the overlapping of the Cretaceous strata of Dorsetshire, 

 the Oxford Clay, about 650 feet in thickness, comes on 

 in great force at Melbury Samplord and Melbury Osmund, 

 where it is underlaid by about 50 feet of Cornbrash. 

 From thence it runs somewhat north-easterly, covering 

 a broad tract of country, by Melksham in Wiltshire, 

 and so on by Chippenham, Cricklade, Fairford, Bamp- 

 ton, Oxford, Bicester, Buckingham, Fenny Stratford 



