424 
GEOLOGY OF THE SECOND DISTRICT. 
2. The surface has been depressed, and rivers have coursed far and wide over land which is 
now elevated, and upon which none are now found. Proof of this is furnished in the numerous 
pot-holes in ledges of rock now distant from any stream, and far above all the creeks in the 
region. 
3. There are long lines of gravel and sand in the form of ridges, which mark distinctly the 
former borders of lakes or seas. 
4. The existence of the tertiary, a marine formation, now reclaimed by elevation, not by 
depression, or by the wearing down of barriers. 
The hypothesis of wide shallow rivers answers better to existing phenomena than any other. 
We require running water, with a current capable of pushing along gravel and sand, for it is 
only by means of fine materials that we can obtain a smooth polished surface ; and it is essen¬ 
tial, too, that it should be borne along in one given direction for a long time, as in forming or 
channelling the deep grooves in the birdseye at Watertown (see Fig. 116, p. 412.) 
Wherever I have observed these deep scorings, I have felt the necessity of calling in the aid 
of running water. Neither icebergs nor glaciers are at all fitted to produce phenomena of this 
kind or character, though they may scratch rocks ; the latter especially must be ranked among 
the agents which produce this effect, but icebergs are among the more unimportant of those 
agents, and can by no means occupy a distinguished place as such in general. 
Subsequent to this period when broad shallow rivers ffowed over our land, it became sub¬ 
merged, and continued beneath the water of the ocean sufficiently long for the deposition of the 
tertiary. During this period, the free and open communication with the Arctic ocean permitted 
the ingress of icebergs, bearing the boulders of the north, the hypersthene rock, etc.; these 
stranded in the shallow waters which surrounded the central part of the now mountainous region, 
that of the Adirondacks. This condition, however, did not continue; the whole country was 
again elevated, and that not once for all, but by several successive upheaves, each followed 
by a long interval of rest; for we find the impressions of many different lines of coast, which 
serve to distinguish the periods of activity of the elevating force from those of its repose. 
This force was not violent, but it affected a wide extent of country : it was paroxysmal in its 
operation, and generally produced but a moderate degree of derangement in the region sub¬ 
jected to its inffuence ; but occasional fractures were made, and surfaces which were previously 
marked by diluvial action, were disjoined, as may now be frequently observed in the valley 
of Lake Champlain. During the period when the tertiary was depositing, we have reason to 
believe that the space occupied by the great lakes was greatly enlarged; and that those de¬ 
pressions which had been made by large streams flowing through the shales of Jefferson county, 
were extended laterally by the action of waves. 
The above hypothesis may appear complicated and unsatisfactory, and to some it may not 
appear why I have supposed the fluviatile era should precede the marine. I remark, that this 
is essential; for the scorings of the rocks cannot have taken place since the marine era: 
they must have been made previous to the deposition of the tertiary, and the whole country 
has since been submerged, and afterwards raised and reclaimed. Tbe groovings leading from 
Watertown to Lake Ontario must have also been made before the tertiary deposit; and the 
