144 EXTINCT MAMMALIA ABOVE DRIFT. [Ch. XIL 



I submitted some of this matter to Mr. A. Henfrey, of London, for 

 microscopic examination, and he informs me that it consists of pieces of 

 small twigs of a coniferous tree of the Cypress family, probably the young 

 shoots of the white cedar, Thuja occidentalism still a native of North 

 America, on which therefore we may conclude that this extinct Mastodon 

 once fed. 



Another specimen of the same quadruped, the most complete and 

 probably the largest ever found, was exhumed in 1845 in the town of 

 Newburg, New York, the length of the skeleton being 25 feet, and it? 

 height 12 feet. The anchylosing of the last two ribs on the right side 

 afforded Dr. John C. Warren a true gauge for the space occupied by the 

 intervertebrate substance, so as to enable him to form a correct estimate 

 of the entire length. The tusks when discovered were 10 feet long, but 

 a part only could be preserved. The large proportion of animal matter 

 in the tusk, teeth, and bones of some of these fossil mammalia is truly 

 astonishing. It amounts in some cases, as Dr. C. T. Jackson has ascer- 

 tained by analysis, to 27 per cent., so that when all the earthy ingre- 

 dients are removed by acids, the form of the bone remains as perfect, 

 and the mass of animal matter is almost as firm, as in a recent bone 

 subjected to similar treatment. 



It would be rash, however to infer from such data that these quadru- 

 peds were mired in modem times, unless we use that term strictly in a 

 geological sense. I have shown that there is a fluviatile deposit in the 

 valley of the Niagara, containing shells of the genera Melania, Lymnea, 

 Planorbis, Valvata, Cyclas, Unio, Helix, &c, all of recent species, from 

 which the bones of the great Mastodon have been taken in a veiy perfect 

 state. Yet the whole excavation of the ravine, for many miles below 

 the Falls, has been slowly effected since that fluviatile deposit was thrown 

 down. 



Whether or not, in assigning a period of more than 30,000 years for 

 the recession of the Falls from Queenstown to their present site, I have 

 over or under estimated the time required for that operation, no one can 

 doubt that a vast number of centuries must have elapsed before so great 

 a series of geographical changes were brought about as have occurred 

 since the entombment of this elephantine quadruped. The freshwater 

 gravel which incloses it is decidedly of much more modern origin than 

 the drift or boulder clay of the same region.* 



Other extinct animals accompany the Mastodon giganteus in the post- 

 glacial deposits of the United States, among which the Castoroides ohi- 

 oensis, Foster and Wyman, a huge rodent allied to the beaver, and the 

 Capybara may be mentioned. But whether the "loess," and other 

 freshwater and marine strata of the Southern States, in which skeletons 

 of the same Mastodon are mingled with the bones of the Megatherium, 

 Mylodon, and Megalonyx, were contemporaneous with the drift, or were 

 of subsequent date, is a chronological question still open to discussion. 



* See Travels in K America, vol. i. chap, ii., and Principles of Geol. chap xiv. 



