126 MICROTIN^ 



and fissure deposits with others to which ordinary stratigraphical 

 methods can be applied. The succession, beginning with the 

 oldest, would seem to be as follows :— 



UPPER PLIOCENE OR CROMERIAN. 



a. Norwich Crag, Weybourne Crag, and a stratum unknown 

 m situ, but represented by the " clay pebbles " occurring in the 

 Lower Freshwater Bed of the Norfolk Coast. 



The voles known from these deposits are all species of Mimomys, 

 namely : 



'^Mimomys plioccenicus Forsyth Major. 

 ^Mimomys reidi Hinton. 

 \Mimomys newtoni Forsyth Major. 



b. Shelly Crag at East Runton. The species known from this 

 deposit are ; — 



"f Mimomys plioccBfiicus Forsyth Major. 



j; Mimomys intermedins Newton. 

 ^Mimotnys savini Hinton. 



c. Upper Freshwater Bed at West Runton. Four genera 

 and ten species are known from this horizon : — 



"fMimomys intermedius Newton. 

 ^Mimomys savini Hinton. 

 ^Mimomys majori Hinton. 

 ^Evotomys sp. (E. glareolus group). 

 "fPitymys gregaloides Hinton. 

 ^Pitymys arvaloides Hinton. 

 ^Microtus arvalinus Hinton. 

 "fMicrotus nivaloides Forsyth Major. 

 '\Microtus nivalinus Hinton. 

 ^Microtus ratticepoides Hinton. 



Among other characteristic mammals of the Cromerian deposits 

 may be mentioned Macaca, MachcBrodus, Trogontherium and 

 Hippopotamus. 



Pitymys gregaloides and Machcerodus have both been found in 

 Kent's Cavern, and their presence suggests that among the many 

 deposits of that famous cave there is a stratum of Cromerian age. 



PLEISTOCENE. 



a. High Terrace of the Thames. Remains of three species 

 have been obtained from a small section in the High Terrace gravel 

 at Ingress Vale, near Greenhithe, Kent. These are : — 



"f Mimomys cantianus Hinton. 

 '\Evotomys sp. {E. glareolus group). 

 Microtus or Pitymys sp. 



