TERTIARY MAMMAL HORJZONS. 39 



Some of the determinations are questionable. Pohlig states 

 that the true Cervus incgaccros hibcniicE is post-glacial, the pre- 

 glacial type being more primitiv^e ; also that the straight tusked 

 ElcpJias aiitiquiis first appears in the north in the IVIosbach 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 ElcpJias 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 laj^er which separates the Forest 

 Bed from the grlacial Boulder Cla^•s. 



2. Glacial and Interglacial, or Mid-Pleistocene 



a. Lozver Mid-Pleistoeeiie. First Iiiterglacial Period [ElepJicis 

 trogojitherii) Lower Stage, Pohlig. 



In climate the early part of this period, immediately during 

 and succeeding the first ice advance, was ver}' extreme. None 

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

 (^primigenins) trogonthcrii or intennediiis and Cervus e/apJuis, 

 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 trogoiitherii, 

 R/iinoceros merckii, R. tiehorhiiius, and the following species of 

 northern type : Ovibos vioscliatns, Cervus (l\lega.ceros) ger/zianicu. 

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

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

 genius) trogontherii succeeded the Elephas vieridionalis of the 

 preglacial beds. 



