He only mentions having here found striations in the three following places along the entire coast of Labrador visited by him; and in regard to two of these, it seems very doubtful that the markings were made by modern icebergs.
Murray’s Harbour:—“This harbour was blocked up with ice on the 20th of July. The water-line is rubbed, and in some places striated” (p. 69).
Pack Island:—“The water-line in a narrow sound was polished and striated in the direction of the sound, about N.N.W. This seems to be fresh work done by heavy ice drifting from Sandwich Bay; but, on the other hand, stages with their legs in the sea, and resting on these very rocks, are not swept away by the ice” (p. 96). If these markings were modern, why did not the “heavy ice” remove the small fir poles supporting the fishing-stages?
Red Bay:—“Landed half-dressed, and found some striæ perfectly fresh at the water-level, but weathered out a short distance inland” (p. 107). The striations “inland” could not have been made by modern icebergs; and it does not follow that because the markings at the water-level were not weathered they were produced by modern ice.
These are the evidences which he found that icebergs striate rocks, on a coast of which he says that, during the year he visited it, “the winter-drift was one vast solid raft of floes and bergs more than 150 miles wide, and perhaps 3,000 feet thick at spots, driven by a whole current bodily over one definite course, year after year, since this land was found” (p. 85).
But Mr. Campbell himself freely admits that the floating ice which comes aground along the shores does not produce striæ. “It is sufficiently evident,” he says, “that glacial striæ are not produced by thin bay-ice” (p. 76). And in “Frost and Fire,” vol. ii., p. 237, he states that, “from a careful examination of the water-line at many spots, it appears that bay-ice grinds rocks, but does not produce striation.”
“It is impossible,” he continues, “to get at rocks over which heavy icebergs now move; but a mass 150 miles wide, perhaps 3,000 feet thick in some parts, and moving at the rate of a mile an hour, or more, appears to be an engine amply sufficient to account for striæ on rising rocks.” And in “American Tramp,” p. 76, he says, “striæ must be made in deep water by the large masses which seem to pursue the even tenor of their way in the steady current which flows down the coast.”
Mr. Campbell, from a careful examination of the sea-bottom along the coast, finds that the small icebergs do not produce striæ, but the large ones, which move over rocks impossible to be got at, “must” produce them. They “appear” to be amply sufficient to do so. If the smaller bergs cannot striate the sea-bottom, why must the larger ones do so? There is no reason why the smaller bergs should not move as swiftly and exert as much pressure on the sea-bottom as the larger ones. And even supposing that they did not, one would expect that the light bergs would effect on a smaller scale what the heavy ones would do on a larger.
I have no doubt that when Mr. Campbell visited Labrador he expected to find the sea-coast under the water-line striated by means of icebergs, and was probably not a little surprised to find that it actually was not. And I have no doubt that were the sea-bottom in the tracks of the large icebergs elevated into view, he would find to his surprise that it was free from striations also.
So far as observation is concerned, we have no grounds from what Mr. Campbell witnessed to conclude that icebergs striate the sea-bottom.