TERTIARY MAMMAL HORIZONS. 39 



Some of the determinations are questionable. Pohlig states 

 that the true Cervus mcgaccros JiibcniicB is post-glacial, the pre- 

 glacial type being more primitive ; also that the straight tusked 

 ElcpJias antiqiius first appears in the north in the Mosbach in- 

 terglacial bed ; elsewhere he refers to it as occurring in the south 

 of France (St. Prest) preglacial beds. 



The remarkable feature of this fauna is the mixture of African 

 and North Asiatic forms. The great ElepJias mcridionalis, a 

 precursor of the Mammoth, is the most characteristic type. 



The first traces of man in the palaeolithic flints of the Cheleen 

 type occur upon this level. 



The climate, judging by the flora and Conchylien fauna, was 

 somewhat cooler than that of the Upper Pliocene. The first 

 arctic flora in England is in a layer which separates the Forest 

 Bed from the glacial Boulder Clays. 



2. Glacial and Interglacial, or Mid-Pleistocene 



a. Lower Mid-Pleistoeene. First Inter glacial Period {^Elephas 

 trogontherii) Lower Stage, Pohlig. 



In climate the early part of this period, immediately during 

 and succeeding the first ice advance, was very extreme. None 

 of the first ice advance fauna is known unless we except Elephas 

 (ypriniigenius^ trogontherii or intennediiis and Cervns elaphns, 

 the latter being doubtfully recorded from the Boulder Clay of 

 England. Here we find the first arctic and sub-arctic types in 

 central Europe. Geologically, these post-glacial deposits consist 

 (Rixdorf Beds) of gravels, conglomerates and sands, constituting 

 (Pohlig) the highest post-glacial terraces, or Higher Terraces. 

 It is marked by the first appearance of Elephas trogontherii, 

 Rhinoceros vterckii, R. tichorJunns, and the following species of 

 northern type : Ovibos inoschatus, Cervns (MegSiceros) ger7/mnic^. 

 Among the new forms we note the megarhine rhinoceros, R. 

 vierckii, as most distincti\'e. The mammoth Elephas {frinii- 

 genius) trogontherii succeeded the Elephas nieridionalis of the 

 preglacial beds. 



