462 PTOceedings of Philosophical Societies. [June, 



south and west shores of the Lake of the Woods are loaded 

 with bowlders, whilst the opposite shore is destitute of them. 

 These evidences of denudation are given as coinciding with the 

 views of Saussure, De Luc, and Buckland. 



2. The Messaluvion is presumed to have been formed in the 

 intermediate state of the earth, which it assumed between its 

 total submergence and its present form. At that period, cen- 

 tral North America is imagined to have been occupied by one 

 o-reat lake ; and the author's evidences to prove this, con- 

 sist of, 1. The series of embankments, and 2. their being com- 

 posed of adjacent rocks, and even of fresh-water materials. 

 3. Rolled masses of neighbouring lakes being reciprocally found 

 in each other. 4. The peculiar nature of the sand and gravel, 

 beneath the mould of the Valley of the St. Lawrence. 5. The 

 mountain-barriers broken through for the passage of rivers and 

 lakes. 6. The analogy of this supposed reservoir to those 

 which have been traced in Germany, Scotland, &c. This enor- 

 mous lake, or rather insulated portion of the ocean, must have 

 extended, in the north, from Hudson's Bay to below Quebec : 

 the eastern boundary being the Allighany range : the western 

 the diluvial hills near the Rivers St. Peter, Red, and Missouri : 

 whilst the waters contained therein must have stood at 1000 

 feet above the level of the sea. 



That the fluid of this great reservoir was saline, is inferred 

 from many genera of fish, of marine origin, being now the in- 

 habitants of the lakes ; which latter are presumed to have been 

 converted into fresli-water by various operations of drainage, 

 &c. Large fresh-water deposits are instanced, as occurring on 

 lakes Huron and Simcoe, extending to Ontario and Erie. 

 Some of the higher beds of these, in the interior, contain 

 Uniones, like those of the present lakes : they are never in a 

 fossil state, and are associated with Planorbes, Phi/sdc, Lymnecc, 

 Melanicc, &c. The banks of the lakes are usually constituted 

 of several steps or terraces, which the author attributes to the 

 various depressions of the waters, occasioned by excessive 

 injuries to the enbankments; but with respect to the great 

 primary lake, he inclines to the belief of its reduction to a 

 oroup by one great disruption. The chaudieres, or pot-like 

 cavities, are described in many situations, and the fluted 

 channellings of various rocks are farther adduced, as exhibiting 

 the abrasive power of water. 



The 3d class, or the alluvial depositions, offer nothing 

 remarkable. The 4th class, or the native debris, is derived 

 from the disintegration of the subjacent, or primitive rocks. 

 The Nipissing, Lake Huron, &c. offer many examples, the 

 materials composing which appear never to have travelled far, 

 but always to have been derived from the contiguous rocks, 

 being unaltered in their outline and angles. 



The paper concludes with the description of a limestone cave 



