414 



rROCEEDTIsTCS OF THE GEOLOGICAL SOCIETT. 



[June 5, 



north of the Alps and Pyrenees. It also corresponds witli the Post- 

 glacial period, as I have used the term, and covers the vast lapse 

 of time, extending from the beginning of the era of intense cold 

 dovrn to the enormous break which separates the Pleistocene from 

 the Prehistoric division of the Tertiary period. 



4. Magnitude of the Interval between the Late Pleistocene 

 AND THE Prehistoric Ages in Britain. 



The magnitude of the break in time between the Late Pleistocene 

 and Prehistoric ages may be gathered not merely from the physical 

 evidence, but also from the disappearance from Britain, in the in- 

 terval, of the following species, of which the last five, and possibly 

 the last seven, have become extinct. 



Glutton. 



Spotted Hyagna. 



Panther. 



Lion, 



Lynx. 



Musk-sheep. 



TJrus. 



Bison. 



Hippopotamus. 

 Lemming. 

 Hamster. 

 Tailless Hare. 

 Lepus diluvianus. 

 Arvicola Gulielmi. 



Cave-Bear. 

 Eihinoeeros liemitceclius. 



tichorliinus. 



Elephas antiquus. 

 primigenius. 



All these animals were eliminated out of the fauna before the 

 Prehistoric deposits were accumulated ; and the remainder lived on 

 through the Prehistoric down into the Historic period. 



5. The Middle Division of the Pleistocene Mammalia. 

 The middle division of the Pleistocene mammalia must now be 

 examined, or that from which Ihe characteristic Pliocene Cervidse 

 had vanished and were replaced by the invading forms from the 

 temperate zones of Northern Asia, It is represented in Britain by 

 the mammalia obtained from the Lower Brick-earths of the Thames- 

 valley, at Crayford, Erith, Ilford, and Gray's Thurrock, by those 

 from the deposit at Clacton, and most probably by those from the 

 older deposit in Kent's Hole, and by the Rhinoceros megarhinus of 

 Oreston. They consist of 



Homo. 



Felis leo (spelaja), Golclf. 



catus, Linn. 



Hyosna crocuta, var. spela;a. 

 Ursus ferox, Lew. tf- Clark. 



arctos, Linn. 



Canis lupus, Linn, 



Tulpes, Linn. 



Lutra vulgaris, Erxl. 

 Bos pi'imigenius, Boj. 

 Bison priscus, Otvcn. 

 Cervus megaceros, Hart. 

 ■ • elapbus, Li7in. 



Cervus Browni. 



capreolus, Linn, 



Ovibos moschatus. 

 Elephas antiquus, Falc. 



primigenius, Blum. 



Equus caballus, Owen. 

 Rhinoceros tichorliinus, Cuv. 



hemitoechus, Falc. 



megarhinus, Christ. 



Sus scrofa, Linn. 

 Hippopotamus major, Desm. 

 Castor fiber, Limi. 

 Arvicola amphibia, Desm. 



The discovery, by the Eev. 0. Fisher, of a flint-flake in the un- 

 disturbed Lower Brick-earths of Crayford, in the presence of the 

 writer, in April 1872, proves that man was living at the time of the 

 accumulation of these fluviatile strata. 



If the mammalia from these deposits be compared with the Pre- 



