Mastodon giganteum in the United States and Canada. 191 



The Mastodon and other quadrupeds have been mired before the de- 

 position of the incumbent silt, for a considerable number of fossil 

 bones have been found by digging through it. Accompanying the 

 bones are freshwater and land shells, most of which have been 

 identified by Mr. Anthony with species now existing in the same 

 region. 



Mr. Lyell observes that the surface of the bog is extremely uneven, 

 and accounts for it partly by the unequal distribution of the incum- 

 bent alluvium, which presses with a heavy weight on certain parts of 

 the morass, from which other portions of the surface are entirely free. 

 He also attributes it in part to the swelling of the bog where it is 

 fully saturated with water near the springs. 



The author is of opinion that the fossil remains of Bigbone Lick 

 are much more modern than the deposition of the drift, which 

 is not present in this district. But although the date of the im- 

 bedding of these mammalian fossil remains is so extremely mo- 

 dern, considered geologically, it is impossible to say how many 

 thousand years may not have elapsed since the Mastodon and other 

 lost species became extinct. They have been found at the depth of 

 several feet from the surface, but we have no data for estimating the 

 rate at which the boggy ground has increased in height, nor do we 

 know how often during floods its upper portion has been swept away. 



Ohio. — The Ohio river immediately above and below Cincinnati 

 is bounded on its right bank by two terraces consisting of sand, gra- 

 vel and loam, the lower terrace consisting of beds supposed to be 

 much newer than those of the upper. In the gravelly beds of the 

 higher terrace teeth both of the Mastodon and elephant have been 

 met with. Mr. Lyell was assured that a boulder of gneiss, 12 feet in 

 diameter, was found resting on the upper terrace, about 4 miles north 

 of Cincinnati, and that some fragments of granite had been found in 

 a similar situation at Cincinnati itself. These facts show that some 

 large erratics have taken up their present position since the older al- 

 luvium of the Ohio valley was deposited. In travelling northwards 

 from Cincinnati towards Cleveland, Mr. Lyell found the northern 

 drift commence in partial patches 25 miles from the former city and 

 about 5 miles N.E. of Lebanon, after which it continually increased 

 in thickness as he proceeded towards Lake Erie. 



New York — Niagara Falls. — In a former paper Mr. Lyell alluded 

 to the position of the remains of Mastodon, 12 feet deep, in a fresh- 

 water formation on the right bank of the river Niagara at the Falls*. 

 He remarks that if we had not been able to prove that the cataract 

 had receded nearly four miles since the origin of the fluviatile strata 

 in question, we should have been unable to assign any considerable 

 duration of time as having intervened between the inhumation of the 

 Mastodon in marl full of existing shells and the present period. The 

 general covering of drift between Lakes Erie and Ontario is consi- 

 dered to be of much higher antiquity than the gravel containing the 

 bones of the Mastodon at the Falls. 



Rochester. — In the suburbs of this city remains of the Mastodon 

 * [See Phil. Mag. S. 3. vol. xxi. p. 554.] 



