The Distribution of Erratics and Drift.

Introduction. By Professor P. F. Kendall, D.Sc., F.R.S. It is desirable that I should explain briefly the way in which this map has come to be published by the Yorkshire Geological Society. In the summer of 1922 I paid a long desired visit to my old friend, F. W. Harmer. I found him in delicate health, as was not surprising in view of the fact that he was then in his 88th year, but he was still happily engaged in the study of the Pliocene Mollusca, upon which he was producing a splendid series of Monographs under the imprimatur of the Palaeontographical Society. Nor was this his sole geological interest, as Yorkshire geologists know full well, for under his guidance they have seen something of the field of his labours in East Anglian Glacial Geology. In the course of our too brief conversation Harmer brought out his contoured map of England upon which he had indicated the distribution of erratics by symbols indicative of their respective sources. Impressed by the beauty and utility of this map, no less than by the devoted industry applied to its production, I urged its author to procure its publication as a whole, and not to be content with the piece-meal issue of detached portions. Mr. Harmer, though willing to bear the cost of its reproduction, was very dubious of the desire or willingness of any Society to undertake the sponsorship of the map and the necessary explanatory memoir, which already existed in a nearly …