Page:The Journal of geology (IA journalofgeology11893univers).pdf/432

sented. The earlier episodes (to use a term not in controversy) may have representatives there in overridden and buried deposits, but, if so, they are obscure and have not been distinctly delineated. In the West, on the other hand, a very considerable series of episodes is well displayed. These embrace not only those presented in New England, but a considerable series of earlier ones not at all (distinctly) represented there. These greatly prolong and diversify the glacial series. In our judgment, it is not simply a doubling of that of New England, but a much higher multiplication. The whole series cannot, therefore, be judged by the incomplete New England representatives. All investigators, we think, or nearly all, agree that the New England glacial deposits fall within a relatively brief epoch and are not much (at least not very distinctly) differentiated. We agree heartily with those who would refer the declared New England drift to one epoch (reserving opinion, of course, regarding remnants of overridden or obscure drift of earlier episodes). New England is little better fitted to be a standard for the interpretation of the whole glacial series than it is for the whole Palæozoic series. In neither case is the series fully and distinctly represented, nor in either case is it typical. This is implied significantly in the relative state of delineation of the formations in the eastern and western sections. With a great preponderance of workers and of skill, no historical divisions of the glacial formations have yet been traced entirely across New England, not even those of an episodal rank. In the interior, on the other hand, something like a score of historical stages have been delineated over broad area. Lines of episodal delimitation aggregating many thousands of miles have been mapped. Any attempt, therefore, to revise the work of the interior by the phenomena of New England is not likely to be more successful than the revision of the Palæozoic series on a like basis.

In classifying personal opinions, a dividing line separating the New England and the western workers is valuable and significant. But a much more significant cleavage plane, we think, may be found between those glacialists who have studied the