North America. 549 
formations on the borders of the Lakes Erie and Ontario; and 
states that in the valley of the St. Lawrence, as far down as Quebec, 
marine shells of arctic character have been found associated with 
coarse detritus. As some of this shelly and boulder deposit lies at 
about 500 feet above the sea, and as Lake Ontario is at a much 
lower level, it is inferred that the sea in which the drift was formed 
extended far over the territory bordering that lake. That the same 
sea extended as far south as 44°, 30! north latitude, is proved by 
the presence on the shores of Lake Champlain, of marine shells; 
which, in their Arctic forms and close agreement with those of 
Uddevalla in Sweden, formerly described by himself, are supposed 
to imply, like those of the St. Lawrence, the former prevalence 
of a cold climate when the drift originated. In regard to the far 
transported boulders, they have in one locality (Beauport) been found 
both above and below the sea-shells. 
The parallel and continuous ridges of sand and gravel, which by 
Mr. Roy and other authors had been considered to be the shores 
of an enormous lake, successively let off, are said to rest on clay of 
the boulder formation, and yet to be occasionally capped by blocks 
of granite and other hard rocks. Comparing them with the Osars 
of Sweden, and stating, from the evidence of Mr. Whittlesey, that 
their base-lines are not so horizontal as had been supposed, Mr. 
Lyell inclines to the belief, though no shells have been found in 
them, that they were all formed under water, and probably beneath 
the sea, as banks or bars of sand, admitting at the same time that 
some of the less elevated ridges may be of lacustrine origin. 
The last observation seems to open out the whole question of 
whether vast freshwater lakes, extending far beyond the area of 
those which now exist, may not, at one period, have covered the 
interior of America. 
This opinion has been long entertained by our associate, Mr. 
Featherstonhaugh, who, in his researches eight years ago, amid the 
western and untravelled tracts, where the sources of the great rivers 
are separated from each other by very slight elevations, discovered 
fluviatile and lacustrine shells, wherever excavations existed or pits 
had been sunk, and at great distances from the courses of the present 
streams. I have the more pleasure in making this allusion to the 
geological labours of Mr, Featherstonhaugh, because he near fifteen 
years ago pointed out some of the chief phenomena connected with 
the retrocession of the Falls of Niagara. He was among the first 
persons, subsequent to his survey of large tracts of the far-west coun- 
try of Arkansas, to assist in the introduction into the United States 
of an acquaintance with the most modern school of English geology ; 
and who, after popularizing the subject by public addresses in 1828 
and 1829, urged upon the government of that country that geologists 
should always accompany geographical surveyors *. 
The view adopted by Mr. Roy, Mr. Featherstonhaugh and 
others, of the former presence of inland lakes in North America 
‘ * 2 Monthly American Journal of Geology, 1831, by Mr. Featherston- 
augh. 
