4i8 Extinct Pleistocene Mammals 



time of the foiraalion of the terrace, which was the Wisconsin epoch. 

 The cementum which on one side, and at one end, spreads outward 

 from between the plates and covers by a continuous layer the whole 

 side of the tooth, is worn off on the other side. That side of the 

 tooth which is the opposite to the grinding surface is worn away so 

 that it presents a smoothly rounded yet bluntly wedge-shaped edge, 

 the enamel and the- dentine being cut by the gravel-worn surface uni- 

 formly, and together showing ?. polished rounded form resembling 

 that of numerous boulders and stones that were subjected to tho wear 

 and tear of the tumultuous and driftladen waters. The enamel of 

 the plates expanciji and becomes a continuous mass, with no dentine 

 nor cementum, and this fact seems to have given the tooth greater 

 firmness and endurance in the root portion than in the crown. If, 

 within the jaw, the tooth had any connection with a porous bony 

 tissue, or terminated at the roots by any processes or vanishing 

 plates of enamel, it shows no trace of such articulation. The view on 

 the left of the photograph* shows the grinding surface and one side 

 almost entirely denuded of cementum which on the other side is so 

 nearly intact as to wholly cover the enamel plates. The view at the 

 right shows the rounded condition of one end of the tooth, together 

 with a portion of that side which is still covered by the spreading 

 cementum. It also shows the rounded form of the root where the 

 enamel and the cementum are equally worn down to a smooth surface. 



This list of elephant remains of Minnesota is probably far from 

 complete. 



There is evidence therefore, within Minnesota, that the mammoth 

 was a denizen here from the time of the loess of the lowan epoch, 

 that he continued through the fourth inter-glacial stage, the Peorian, 

 survived the intensity of the Wisconsin ice epoch (which was the last) 

 and lived on the surface of the Wisconsin till sheet long afterwards; 

 and, considering his late extinction in Siberia, it is reasonable to infer 

 that the ancestors of the American Indian were familiar with his enor- 

 mous bulk, and slew him with their stone-headed arrows. 



As to the Mastodon, it is very probable while no remains have 

 been sufficiently demonstrated within the. limits of Minnesota, and 

 those of the Mammoth are well verified, and we cannot safely there- 

 fore affirm that the Mastodon ever inhabited the state, yet that he did, 

 and that his remains are liable to ba discovered. Judging from the 

 comparative numbers of the mastodon and the elephant found at the 

 celebrated Big Bone lick in Kentucky, it seems that the range of the 

 mastodon was more southerly than that of the mammoth. Of the 

 teeth found at that celebrated locality, the relative numbers were 

 such that the mastodon were five to one of the mammoth. 



2. Castoroides ohioensis. Next in order of discovery, was the great 

 extinct Ohio beaver, whose size was about that of the present black 

 bear. This discovery was made at Minneapolis, at the corner of 

 Washington avenue and Fifteenth avenue north in 1879, in the pro- 

 cess of digging for a cistern. There is a full description of this dis- 



* Plate X. 



