CHAPTER IV. 



PART III. 

 FOSSIL EEMAINS OF KUMINANTS. 



DILUVIUM OF THE VALLEY OF THE THAMES FOSSIL BOVID.E BISON PRISCDS 

 BOS PBIMIGENIUS BOS LONGIFKONS. 



DILUVIUM OF THE VALLEY OP THE THAMES. The banks of 

 the Thames and of its tributary streams, are in great part com- 

 posed of an ancient alluvial silt, or brick earth, many yards in 

 thickness, which contains, in some localities, great numbers of 

 fossil bones of Mammalia, of many extinct, and some recent 

 species, with existing kinds of land and river shells. Among 

 the latter there is a freshwater bivalve, a species of Cyrena, 

 which is supposed to be identical with one that abounds in the 

 river, at Alexandria ; and an Unio, of which the living ana- 

 logue inhabits the lakes of Auvergne in France. 1 



At Erith, on the south bank of the Thames, a spot well 

 known for its beautiful sylvan scenery, this deposit attains an 

 elevation of 40 feet above the level of the river ; and at Maid- 

 stone, (ante, p. 302,) it is 60 feet above the Medway. At 

 Grays, in Essex, opposite Gravesend, there are extensive cut- 

 tings of these deposits in the brick-fields, in which the following 

 section is exposed. 1. Gravel and sand. 2. Loamy sand and 

 brick-earth. 3. Ferruginous sand, shells, and gravel. 4. The 

 Chalk, which is the foundation rock of the country. 



From this locality alone have been obtained bones of the 



1 See a highly interesting communication on these deposits, by John 

 Morris, Esq. (of Kensington) ; " Magazine of Nat. Hist." vol. ii. p. 539. 



