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CHAPTER XII. 



FOSSIL MOLLUSCA (CAINOZOIC, OR TERTIARY). 



Nowhere is a knowledge of fossil bivalves and uni- 

 valves of such great importance as in the Tertiary 

 strata. All other kinds of fossils are few in compari- 

 son with their abundance. 



The pursuit of Tertiary geology takes the student 

 into some of the most delightful spots in southern and 

 eastern England, and to wide stretches of heath and 

 common which still remain unenclosed. The sandy 

 nature of the strata of many Tertiary formations 

 tends to a *' hungriness " of surface soil, especially in 

 districts south of the Thames, where the morainic 

 matter, or Boulder-clay of the Glacial period, is not 

 strewn over the older deposits. 



In Dorsetshire and Hampshire the Lower and 

 Middle Eocene beds are frequently rich in fossil plants 

 (as in the clay-pits on the west side of Bournemouth). 

 The vertical strata of " pipe-clays," with their beauti- 



