390 



THE AGE OF MAMMALS 



Epoch 

 Present 



4th, Wiirm, Glacial Epoch 



Riss-Wiirm Interglacial 

 (later part) 



Riss-Wiirm Interglacial 

 (earlier part) 



Sd, Riss, Glacial Epoch 

 Maximum 

 Glaciation 



Fauna Vegetation 



Cervus elaphus Forest 



I Elephas primigenius 

 \ Rhinoceros tichorhinus r Tundra 

 [ Rangifer tarandus 



Elephas primigenius 

 I Rhinoceros tichorhinus 

 [ Equus cahallus J 



I Elephas antiquus 



■j Rhinoceros merckii ( Forest 



[ Cervus elaphus J 



I Elephas primigenius 

 Rhinoceros tichorhinus ( Tundra 

 Rangifer tarandus J 



(Nehring) (G. de Mortillet) 

 Forest Neolithic 



Pal.-eolithic 

 Magdalenian Culture 



Grassy steppes Steppe 



Solutrian Culture 



Tundra 



Mousterian Culture 



Rhinoceroses. — The three great rhinoceroses characteristic of the Eu- 

 ropean Pleistocene, which probably belonged to two separate phyla, Asiatic, 

 or Sumatran, and African, are of distinct geologic value. Of the former 

 phylum, D. etruscus of the Val d'Arno ^ is a small animal of Pliocene and 

 early Pleistocene times, distinguished by brachyodont or short-crowned 

 grinding teeth, and long, slender limbs, two horns, the larger of which is 

 posterior, and the absence of cutting, or front teeth; it is remotely related 

 to the Dicerorhinus, or Sumatran phylum, but differs in the absence of cutting 

 teeth. It belongs with the First Fauna, and does not survive into mid- 

 Pleistocene times. 



Succeeding this animal in early Pleistocene times both in Great Britain, 

 France, and Italy, also surviving with the Second Fauna of the mid-Pleis- 

 tocene of all Europe, is the broad-nosed rhinoceros, known as D. megarhinus, 

 or D. merckii. It is distinguished from D. etruscus by long-crowned, or 

 hypsodont grinding teeth; it resembles it in the smaller anterior and larger 

 posterior horn, and in the elongation of its limbs and feet. In mid-Pleisto- 

 cene times it became covered with hair, attained a great size, and was very 

 abundant and characteristic. 



The third species, the woolly rhinoceros (D. antiquttatis, D. tichorhinus), 

 is, however, the distinctively cold weather, steppe, and tundra form, and 

 belongs with the Third Fauna. Like the foregoing species, it has no front 

 teeth, hence has been improperly considered as related to them, but it 

 really belongs to the modern African group of Atelodus (Diceros), distin- 

 guished by a very large front horn and small posterior horn as in the exist- 

 ing "white rhinoceros" (R. simus). 



The names of these three rhinoceroses are almost hopelessl}^ confused 

 in the early literature, though the characters were very clearly defined by 

 Dawkins.- Both in the megarhine and tichorhine rhinoceroses and in old 

 individuals of the Etruscan, the septum supporting the nasal bones becomes 

 more or less fully ossified, to support the stout anterior horns. 



* Dawkins, W. Boyd, On the Dentition of Rhinoceros etruscus Falc. Quart. Journ. Geol. 

 Sac, Vol. XXIV, 1868, pp. 207-218. 



^ Dawkins, W. Boyd, The British Pleistocene Mammalia, Pt. I, Introduction, 1866. 



