BRITISH FOSSIL SPECIES 129 



Explanation ok Fig. 65. 

 All the specimens are from the Upper Freshwater Bed at West Runton. 



1. Microtuti arvalinu/i Hinton. Right m-^, young, with ephemeral com- 



plications; la basal view. 



2. M. arvalinus. Left wij. 



3. M. arvalinus. Right m^ and m^ [Savin Coll., No. Gi4.8). 



4. M. arvalinus. Right r/ij (Savin Coll., No. 644.8). 



5. 31. arvalinus. Right Wj {Savin Coll., No. 654.1). 

 0. M. arvalinus. Left Wj. 



7. M. arvalinus. Left m^ {Savin Coll., No. 643.10). 



8. M. arvalinus. Left m^ {Savin Coll., No. 643.0). 



9. AI. arvalinus. Right r«i {Savin Coll., No. 7.25). 



10. M. arvalinus. Left ?«j {Savin Coll., No. 643.1). 



11. iM. arvalinus. Left m^ {Savin Coll., No. 643.2). 



12. M. arvalinus. Right wtj. 



13. M. arvalinus. Left m^ {Savin Coll., No. 643.11). 



14. M. arvalinu.s. Right m^. 



15. M. nivaloidcs Forsyth Major. Right »»i {Savin Coll., No. 12.26). 



16. 31. nivaloides. Right m^ {Savin Coll., No. 654.5); 16a part of basal 



view. 



17. 31. nivaloides. Left m^. 



18. 3J. nivaloides. Right m^. 



19. 31. nivaloides. Left nii {Savin Coll., No. 7.11). 



20. M. nivaloides. Left Wj {Savin Coll., No. 643.6). 



21. 31. nivaloides. Left Wj. 



22. M. nivalinus Hinton. Left Wj. 



23. 31. nivaloides. Left m^ {Savin Coll., No. 643.4). 



24. 31. nivalinus ? Left m^ and in^ {Savin Coll., No. 8.17). 



25. 31. nivalinus. Right Wj {Savin Coll., No. 8.18). 



26. 31. nivalinus. Right »«i {Savin Coll., No. 643.5). 



27. 31. nivalinus ? Left ?«i and Wj {Savin Coll., No. 643.12). 



28. 3fl. nivalinus. Left m^, type {Savin Coll., No. 8.16). 



29. 31. ralticejioides Hinton. Left m^ and 7«2 {Savin Coll., No. 653.3). 



Trogo)itJierium aud the remaiiis of many other species indicat- 

 ing a rich mammalian and molluscan fauna occur also at Ingress 

 Vale. The whole assemblage closely resembles that known from 

 Cromerian horizons and suggests that there is no great difEerence 

 of age between the portion of the High Terrace represented at 

 Ingress Vale and the Upper Freshwater Bed at West Runton. 



h. Early Middle Terrace of the Thames (typical locality, 

 Grays Thurrock, Essex). Three species are known viz. : — 



"fArvicola prceceptor Hinton. 

 \Evotomys sp. {E. glareolus group). 

 "fMicrotus agrestoides Hinton. 



Macaca, Hippopolamus, Rhinoceros megarJiinus and Elephas 

 anliqmts are characteristic survivals from the Upjser Pliocene 

 occurring in this horizon. The species of Arvicola is not closely 

 related to modern species of that genus ; it seems to be a direct 

 descendant from one of the species of Mimoinys occurring in the 

 Upper Freshwater Bed. Very similar forms are found in the 

 latest " Cromerian " horizons as in the so-called Upper Fresh- 



V.L. K 



