Mammals 19 



proposed to remove these animals from Elephas, placing E. im- 

 perator in Archidiskpdon of Pohlig and E. jeffersoni in Parelephas 

 of Osborn.* 



Long before the elephant group reached America, this land 

 was occupied by other huge mammals, the Titanotheres. It was 

 long supposed that this superfamily was confined to North 

 America, but more recently remains apparently referable to it 

 have been discovered in Europe. Numerous Titanotheres, 

 described by Osborn, Cope, Leidy and Marsh have been found 

 in the earlier Tertiary strata of Colorado. They appear to have 

 died out near the middle of Oligocene time; for what reason, 

 we do not know. In appearance, the Titanotheres were more 

 like rhinoceroses than any other animal known to us. The 

 rhinoceroses have of course survived in Asia and Africa, but 

 they formerly abounded in America, several species existing 

 in Colorado. In the Colorado Museum of Natural History, two 

 skeletons have been cleverly mounted, with a restoration on one 

 side, looking like a modern stuffed specimen, and the bones ex- 

 posed on the other side. One of these, from Weld County, is 

 called Trigonias osborni; the other, from Yuma County, is Tele- 

 oceras fossiger. Additional details, with figures, are given in the 

 Scientific Monthly for September 1923. 



In any review of the extinct animals of Colorado, we should 

 not omit the Camelidae, the family of camels and llamas. It 

 was long ago recognized that the South American llama and vicuna 

 were allied to the Old World camel and dromedary, a very sur- 

 prising fact in view of their wide separation. The key to the 

 mystery was supplied when it was discovered that members of 

 this group formerly spread all over North America, which was 

 in fact the place of origin of the whole series. Extending their 

 range across Asia, the camels finally reached North Africa, while 

 the llamas, going southward, found a home in the Andes. It is 

 as if mankind and his civilization perished in Europe, to survive 

 in America and New Zealand. It has not rarely happened that 

 a once dominant and wide-spread race has been reduced to a few 

 forms occupying regions remote from the original home of the 



*Hay (1924) enumerates several Colorado records of the Elephas columbi of Falconer, 

 but Osborn shows that this species has been confused with others. In true E. columbi, accord- 

 ing to Osborn, the ridge-plates of the teeth do not exceed six in 1 00 mm. 



