Geological Society. 127 



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

 know how often during floods its upjjer j^ortion 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. 



Neio 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 liigher antiquity than the gravel containing the 

 bones of the Mastodon at the Falls. 



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

 giganteum were found associated with existing species of Mollusca 

 in gravel and marl below peat, 



Ge?iesee. — Here remains of the Mastodon giganteum were found 

 wath existing shells in a small swamp in a cavity of the boulder for- 

 mation, so that the animal must have sunk after the period of the 

 drift when a shallow pond fed by springs was inhabited by the same 

 species of freshwater mollusca as now live on the spot. 



Albany and Greene Counties. — Mr. Lyell examined, in company with 

 Mr. Hall, two swamps west of the Hudson River, where the remains 

 of Mastodon occurred in both places at a depth of four or five feet, 

 precisely in such situations as would yield shell marl, and peat, 

 with remains of existing animals in Scotland. Cattle have recently 

 been mired in these swamps. 



According to Mr. Hall the greatest elevation at which Mastodon 

 bones have been found in the United States is at the town of Hins- 

 dale, situated on a tributary of the river Allegany in Cattarauf>-us 

 county in the State of New York, where they occur at an elevation 

 of 1500 feet above the level of the sea. 



Maryland. — In the museum at Baltimore, Mr. Lyell was shown 

 the grinder of a Mastodon, distinct from M. giganteum, and which 



