113 



their distribution their size is as great as near their source. 

 They are found deposited according to the configuration of the 

 country. 



Prof. Rogers said he wished to recur to his question as to the 

 epoch of the mastodons. He had been long seeking light upon 

 this subject. There was no doubt that in many places the re- 

 mains of this animal had been found above the drift, in basins on 

 its surface. They had been said to have been also discovered under 

 the drift. It was out of all analogy to suppose that the race had 

 existed at different dates at different places. How then were 

 these discrepancies to be explained ? He thought the facts of 

 the case demanded a more thorough investigation. He had sup- 

 posed that at Big Bone Lick the bones had been found in a drift 

 formation. He would ask Mr. Foster whether at that place there 

 was the same continuous boulder stratum as on the upland ? 



Mr. Foster replied that where the strata of clay had been cut 

 through, the superincumbent boulders had dropped down into the 

 valley, and rested on the clay imbedding the bones. The southern 

 limit of the boulders, he said, was about lat. 40°. Very few are 

 found south of the Ohio. They rest on the yellow clay. 



Prof. Rogers said he thought there was the same room for 

 doubt as to the age of the bones in question as in the case of the 

 human remains found at Natchez, of which an account had been 

 given by Dr. Dickerson. In a valley of denudation the deposit 

 at the bottom may have been swept over into it, and be in reality 

 composed of more recent materials than the higher formations 

 in its vicinity, as was shown in the Mississippi case. He was 

 still inclined to doubt the extensive character ascribed to the blue 

 clay of Ohio, by Mr. Foster, and the consequent inference of 

 the high antiquity of the relics entombed in it. He could not 

 resist the impression that this deposit would prove to be a local 

 one, thrown down by a circumscribed body of water. There 

 had been so much doubt as to the age of the specimens from 

 Carolina when presented at Philadelphia, that he had felt him- 

 self warranted in asking of Dr. Gibbes specific evidence as to the 

 actual material from which, and from under wliich they were dug 

 out. He said that he must dissent from Mr. Foster and Mr. Desor, 

 as to their theories of the drift. He was no glacialist in any 



PROCEEDINGS B. S. N. H. 8 BUY, 1849. 



