On the superficial deposits at the estuary of the South Esk

Abstract

Before describing the strictly estuary deposits which are found at the mouth of the South Esk, it will be necessary to allude shortly to the subjacent covering of boulder clay which generally overlies the rocks of Forfarshire, and in point of chronological order immediately precedes the laminated marine clay. As in other localities, the boulder clay of this district consists chiefly of the debris of rocks which it overlies. Strangers generally remark on the immense number of small boulders, or ‶bouls,″ as they are termed, scattered over the fields in this and the adjoining county of Kincardine. On examination, these are found to be smooth round masses, mostly of quartz and porphyry, evidently identical with the boulders of the Old Red Sandstone conglomerate. They are generally scratched in the direction of their long axes, apparently by ice-action during the glacial era, but the rounding and polishing which gives form to the stones undoubtedly was effected during the formation of the conglomerate. In the denudation of the conglomerate, the great mass of land ice, which is supposed once to have enveloped our island, got these boulders ready made. Transported boulders are however of frequent occurrence in this deposit. Thus on the hill of Sunnyside, near Montrose, pieces of red shale are found, derived from the synclinal axis many miles to the north-west, and at 100 feet lower elevation. Again, large blocks of gneiss are often met with, some of them several tons in weight, which must have come from the Grampians,