T. Sterry Hunt

“ The transportation of masses of rock by icebergs as they drift along the currents which set from the polar regions, and the distribution of their loads over the bottom of the ocean as the bergs melt away, present, in the view of many, a repetition of the process by which in remote times the surfaces of the present continents were covered with the drift materials. ”

“ As the process of elevation proceeded, and the northern current found its passage across the eastern region to the sea, by channels further and further east, the conditions became such as to permit the deposition, from seas comparatively undisturbed, of the stratified clays and sands, which are seen in so many cases to rest upon the bowlder clay, and are found with their characteristic fossils at elevations of 600 and even 800 ft. above the sea; while others, though so far as known without organic remains, are met with at still higher levels. ”

“ In the Alpine regions of Europe the effects thus produced are so remarkable, and spread over such extensive districts, that many geologists who have studied them are disposed to refer all the phenomena of the unstratified drift to the action of glaciers; and in this view they are confirmed by finding unmistakable evidence that the action of the glaciers formerly extended far beyond their present limits. But the unstratified drift is found to extend over vast regions where it is difficult to conceive that mountain glaciers could ever have found their way ”

“ These in great part submerged and half stranded masses, urged by current, wind, and tide, would plough and furrow the bottom, there piling up the unstratified heaps of bowlder clay, to which the earth and rocks borne by the melting ice would contribute.—The formation of the diluvium or bowlder drift is thus, according to either view, the result of the action of ice. ”

“ This may be described as a heterogeneous mass of clay with sand and gravel in varying proportions, enclosing the transported fragments of rock, of all dimensions, partially rounded or worn into wedge-shaped forms, and generally with surfaces furrowed or scratched, the whole material looking as if it had been scraped together. ”

“ As already described in the article Bowlders, they are often of great dimensions, and increase in size as the deposit is traced toward its source to the northward. In Russia they have thus been identified with ledges more than 800 m. distant toward the north. Bowlders of the same kind of granite, easily recognized, traced from Moscow to St. Petersburg, vary from two or three feet in diameter at the former to as many yards at the latter point. Instances of these phenomena are everywhere to be seen in the northern United States. ”