Geology of Canada. 13 
stones, with the rocks of the Clinton group. All of these are well 
characterized by their respective fossils, and are spread out quite 
undisturbed at a very gentle dip of about thirty-five feet in a mile. 
The thickness of these rocks, as exhibited in a section across the — 
Grand Manitoulin and La Cloche Islands, was found to be from 
‘ the base of the Potsdam sandstone to the top of the Niagara lime- 
stone, 1,273 feet. 
Passing to the east, we find that the syenitic rocks have divid- 
ed near where they cross the Ottawa, and taking a southward 
course, are spread over a considerable extent of country between 
the Ottawa and the St. Lawrence. Crossing this river below 
Kingston, they constitute the greater part of the Thousand Isles, 
and are extensively developed in the northern counties of New 
York. 
The country thus bounded on the west and north consists of a 
broad valley of twelve to twenty miles on the north, and thirty to 
forty miles on the south side of the St. Lawrence, which at its 
southwestern extreme, includes the valley of the Richelieu and 
the northern part of lake Champlain. On the southeastern side 
of this is a mountain belt of from twenty-five to thirty miles in 
width ; this is the prolongation of the Green Mountains of Ver- 
and Notre 
EE a PM nrcrcne ame | J “ Z 4 a 
to mont, which further north constitute the Shickshock 
Pr Dame mountains of Gaspé. This mountain range, coincident 
| with the course of the river, is bounded at its southeastern base 
| by a valley of gently undulating land, from twenty to thirty miles 
an width, which may be traced from the upper part of the Con- 
, necticut river to the upper portion of the St. Francis; thence by 
the eastern branch of the Chaudiére to the Riviére de Famine, a 
tributary of the Chaudiére, the valley is continued in the course of 
the St. John’s until further on, it falls into the valley of the Risti- 
2d quite into the Baie des Chaleurs. The 
“mountain range, and the same geological 
formations appear continuous without. 
If a line be drawn from St. Scholastique, upon the north shore 
of the Ottawa, passing forty miles S. E. to Montreal, and thence 
‘the Connecticut river, in the north of Vermont, we 
county of Beauharnois, where it spreads out toa cousidera- 
€ width, and passing into the state of New York, divides against 
the syenftic formation. Sweeping around its base, one portion 
ses up the valley of the St. Lawrence, and the other is devel- 
q 
