ANCIENT MAMMALS OF BRITAIN. <99 



in the country, or are existing in other parts of Europe. Our 

 regular survey will, therefore, commence with the Mammals 

 found in the caverns and the various more or less nearly 

 contemporary brick-earths and gravels, which generally form 

 high-level plateaux in our river valleys, and are for the most 

 part of more recent date than the epoch of maximum ex- 

 tension of the ice of the Glacial Period. The whole of these 

 deposits belong to the Pleistocene, or latest Geological Period ', 

 and the next in point of age are the formations exposed on the 

 east coast of England, in the counties of ' Norfolk, Suffolk, 

 and Essex. The highest of those deposits to which we shall 

 specially refer is the series usually denominated the "forest- 

 bed," so called on account of the relics of an ancient forest 

 \\hich it contains in situ. Although clearly antedating the 

 Glacial Epoch, there is some doubt as to the precise geo- 

 logical age of this deposit, some authorities referring it to 

 the top of the Pliocene Period, while others consider that 

 it forms the base of the Pleistocene. As the majority of 

 the Mammalian remains yielded by this bed belong to exist- 

 ing species, the latter view is the one which we feel inclined 

 to adopt. Below the forest-bed come the crags, of which 

 the Norwich crag belongs to the upper portion of the Pliocene 

 Period, while the Red and Coralline crags may be assigned 

 to the lower division of the same. The Tertiaries of the 

 Hampshire and London basins belong solely to the Oligocene 

 and Eocene Epochs ; and t'.e mention of the ages of these 

 different horizons may accordingly be reserved till we come 

 to the consideration of their fauna. 



With regard to the epoch of our caverns and brick-earths, 

 it may be observed, in the first place, that by far the great 

 majority of the species whose remains are entombed in the 

 various deposits, are still existing, although most of the larger 

 ones have disappeared from Britain, having been either 



