312 LLOYDS NATURAL HISTORY. 



Pliocene, and a Vole {M. intermedius) intermediate in size 

 between the Water- Vole and Field- Vole differs from both in 

 having distinct roots to the molar teeth. In the Insectivorous 

 Order we have the Mole, and the Common and Pigmy Shrews, 

 as representatives of the existing British Fauna ; while the 

 Russian Desman (Myogale moschata) is now found only in 

 the districts between the rivers Don and Volga, where it leads 

 an aquatic life, not unlike that of our Water- Vole, save that 

 its habits are insectivorous instead of herbivorous. 



The few Cetacean remains from the Forest-bed appear all 

 referable to existing forms, and indicate the same mixture of 

 southern and northern forms as characterises the land Fauna. 

 Among these are the southern Right Whale {Balcena australis), 

 a large Fin-Whale (Balcsnopterd), the Sperm-Whale — which 

 still occasionally straggles as far north as Britain — tlie Killer, 

 or Grampus (Orca gladiator), the False Killer (Pseudorca cras- 

 sidens) — originally described from a skull from the fens near 

 Stamford, but subsequently found hving in the North Sea, — 

 the Arctic Narwhal (Monodon monoceros), and White Whale 

 {Delphinaplerus leucas), the Common Dolphin, the Bottle- 

 nosed Dolphin, and the Porpoise. 



We now come to the shelly deposits of the east coast, locally 

 known by the term of " Crags," a name which has been adopted 

 into geological nomenclature. These beds admit of a three- 

 fold division, namely, the Norwich, Fluvio-Marine, or Mam- 

 maliferous Crag, the Red Crag, and the Coralline, or White 

 Crag. The former, which is partly of fresh-water and partly of 

 marine origin, shows a Molluscan Fauna of a decidedly northern 

 type, and has at its base a bone-bed in which Mammalian re- 

 mains occur in considerable quantities. The Red Crag takes 

 its name from the colour of its sandy beds, and likewise con- 

 tains a bone-bed in which the fossils are mainly converted into 

 phosphate of lime, and are thus valuj^ble gs a source of arli- 



