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GEOLOGY OF THE SECOND DISTRICT. 
CHAPTER XII. 
On Drift. — Grooves and Scorings of the Rocks of the Second District. Hypotheses. —^ 
Depression or Submergence, and Gradual Rise. — Glacial Theory. — Remarks on the 
necessity of a classification of facts, etc. 
In this chapter, I propose to condense into one view the facts in relation to drift and the 
subjects related thereto, so far at least as they receive illustration in the geological structure 
of the Second district. For a full and clear understanding of these phenomena, it is necessary 
to bring together the facts relating to each, such as the distribution of boulders, the scoring 
of rocks, the position of the tertiary, etc. I shall therefore recapitulate briefly these facts, 
preparatory to summing up the inferences which may be deduced from them. 
1. Distribution of boulders. It has been stated that the boulders and drift of the north are 
arranged in a belt between two and three hundred feet above the level of the great lakes, at 
the bases or upon the lower terraces of the hills which lie between the Champlain and the St. 
Lawrence waters. At least they are more abundant at this height than either below or above, 
though they occur between two and three thousand feet higher. Boulders may be divided into 
two classes : 1st, those which evidently belong to regions remote from their present location ; 
and 2dly, those which belong either to the rock immediately beneath the surface, or to one 
but a short distance therefrom : the former class are rounded, and the latter angular. The 
boulders on the east side of Lake Champlain belong almost exclusively to the rock immediately 
below the surface, for which I shall be able to give a reason. 
2. The scorings of rock, or scratches. Their direction conforms to that of the great valleys. 
In the Champlain valley, it is nearly north and south ; and in the St. Lawrence valley, north¬ 
east and southwest. It is necessary to class with these the deep groovings noticed under 
Jefferson county (see p. 369). Perforations belong to another class of phenomena, being 
produced always by waters moving in eddying currents, and carrying around stones, sand and 
gravel. 
3. Tertiary of Champlain. This is deposited from quiet waters, and always overlies the 
scored and grooved surfaces. It is marine, and contains many fossils and some boulders, but 
the latter are extremely rare except in a few places. In many places the tertiary lies beneath 
