vies go? eee: 
40", al 
12 On the Physical Geology of the United States, &c. 
over the territory occupied by Missouri, Iowa, Illinois, Indiana, 
Michigan, Ohio, and Upper Canada, and thence eastward over 
Lower Canada and New York through the St. Lawrence and 
Mohawk valleys. The branch through the Mohawk valley 
would be deflected more to the E. and S. BK. by the polar cur- 
rent through the Champlain and Hudson valley,* and again to 
the S. and S. W. by the Green Mountains and Highland ranges. 
A circular flow would thus be induced, and nearly all the ma- 
terials transported by the equatorial current, from whatever 
sources they had been derived, may be supposed to have been 
deposited within this great eddy. 'These currents, as conse- 
quences of known dynamical laws, must have flowed in the way 
indicated from the period of the elevation of the primary ranges, 
until the continent was raised above the level of the ocean. 
We know also that marine currents are constantly transporting 
earthy and organic materials, depositing them at places more or 
less remote from their origin, and that they now circulate over 
vast areas of the ocean. 
It is believed therefore, that the ocean currents offer a satisfac- 
tory explanation of the transportation and deposition of the im- 
mense mass of the sedimentary rocks between the primary ranges 
north of the great lakes and the Gulf of Mexico, and between the 
Blue Ridge and the Rocky Mountains. 
Other areas of similar rocks and connected with that described, 
occupy a part of Vermont, the southern part of Lower Canada, 
parts of New Brunswick, Nova Scotia, Maine, Massachusetts and 
Rhode Island. They are believed to be due to the same causes 
acting more extensively than we have considered them, in which 
the mountain regions of northeastern New York and of New Eng- 
land were islands. Even"this is supposed to be but a limited view 
of the effects of these currents in the northern hemisphere, and the 
similar rocks of Europe may have been due to the same causes— 
the same currents. The uniformity of composition of the par- 
ticular masses, whether thick or thin, their similar mineralogical 
* The evidence of acold current from the north through the Champlain and 
Hudson valley, is treated of and believed to be established in the Geological Re- 
port of New York, by the author of this paper, in Part IV, Vol. 1, pp. 150-154, 
225, 293, 299, 274-275, 277-278, in 4to. Albany, 1843. 
The subject of currents as aiding in the transport of materials, scoring of rocks, 
influence on organic life, and the evidences of their directions, are treated of under 
the quaternary, drift, and red sandstone formations in the same work. 
