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Beneath is a thick, uniform stratum of blue clay ; over it an 

 equally regular stratum of yellow clay, on the surface of which 

 are found boulders of native copper and granite. Remains of 

 Mastodon, fossil Elephant, and Castoroides are found in the blue 

 clay, and in erosions in the yellow filled with fresh water marl. 

 Such is their position at Big Bone Lick, the great charnel house 

 of these remains. At this place a small creek traverses a nar- 

 row valley of three-quarters of a mile in width, and empties into 

 the Ohio. The swamp is filled in with blue clay, and on the 

 adjacent banks the yellow clay is visible. The presence of the 

 bones in the blue clay, which underlies the yellow, led him to 

 consider this valley as one of denudation. The face of the 

 country he thought had undergone no very great change since 

 they were buried. If we suppose the Ohio to have been dammed 

 up by a barrier five hundred feet high, all the level part of the 

 State and the adjoining country would be an immense lake, the 

 tranquil deposition from which, would account for the extensive 

 clay formation. Some idea of its extent might be obtained from 

 the fact that it had been traced over 8° lat., and that at Detroit 

 its thickness is one hundred and ten feet. The position of their 

 remains in this clay would give to these animals a very high 

 antiquity, long anterior to man. He thought there was evidence 

 of the existence of such an extensive lake at a former epoch, in 

 the terraces and other geographical features of the country. Its 

 northern part would border on a region which three quarters of 

 the year would be one of ice and snow. This would explain 

 the presence of the boulders in the South, which must have come 

 from this district, as it would admit of the supposition of the 

 transporting agency of icebergs, by which he had no doubt they 

 had been brought down. The geographical features of the 

 country excluded all possibility, he thought, of the action of 

 glaciers. It seemed to him impossible that they could have 

 traversed a nearly level plain, for a distance of six hundred 

 miles. Neither was he inclined to believe in the power of water 

 as a transporting agent in the present case. It is difficult to 

 believe, he said, that water could have brought such masses of 

 native copper a distance of sixty miles. Had such a power been 

 in action, the largest and heaviest boulders would have been 

 dropped first. But it is found that at the most southern limit of 



