Association of American Geologists a,nd Naturalists. 273 



coasts of mountain islands, such as, on one hypothesis, the Adirondack 

 region and the White mountains were, is contradicted by the important 

 fact, made known by Prof. Hitchcock and Prof. Emmons, that those 

 high tracts have not been centres of dispersion, but like every other 

 spot, have been invaded by the drift from the north. But there is also 

 another opposing consideration. The extent of the drift throughout the 

 northern regions of this continent is immense ; yet by this theory nearly 

 the whole of it and of northern Europe was depressed below the sea at 

 that period, and I confess I look over that vast imagined ocean of the 

 north in vain for the conditions of physical geography, compatible with 

 the arctic winter supposed. The conceived state of things, an enor- 

 mous expanse of waters, with here and there an island, in place of a 

 broad continent in the higher latitudes, is the very converse of that dis- 

 tribution which is compatible with great cold and with islands and fields 

 of ice. 



In reference to the generalizations of Prof. Mather regarding the di- 

 rection and agency of oceanic currents at the period of this assumed 

 depression, I cannot refrain from expressing my belief that the hypothe- 

 sis of an ancient Gulf Stream, not flowing however up the valley of the 

 Mississippi, but, during certain periods at least, along the line of our 

 great Atlantic tertiary belt, is sufficiently in accordance with the proba- 

 ble ancient configuration of the land and with geological memorials, to 

 promise important aid in certain speculative questions in our geology. 

 I encounter, however, some difficulty in understanding how the two 

 great currents, the polar and the southern one, would produce a result- 

 ant movement which would strew the drift in the direction which it ob- 

 viously took. The general course of the furrows in the rocky surface, 

 and of the trains of detrital matter, is from about north northwest to 

 south southeast, and I cannot conceive how a current setting to the south- 

 west could be turned by one setting in the opposite direction into a south- 

 easterly course, or how a smgle direction could, by such a conflict, be 

 imparted to such a vast area of waters, as wide in latitude and longi- 

 tude as the region now occupied by the drift ; or how, if it could be 

 thus deflected, it should be able to retain the high velocity which it must 

 have held in order to distribute the bowlders in their long narrow trains, 

 to round the angles of the hills, and score and gutter the very hardest 

 rocks. 



Let us now give our attention for a moment to the paroxysmal theory, 

 which I cannot but think will be found, on careful examination, to be 

 more in agreement with the admitted laws of physical dynamics than 



