I. Introductory That north-eastern angle of Scotland which lies between the Moray Firth and the Firth of Tay presents some special features of interest in connection with the history of the Glacial Period, inasmuch as it seems to have been less heavily covered with ice than the rest of Scotland. Nevertheless, no part of the area appears to have escaped invasion, for the ice which filled the basin of the Moray Firth extended over all the southern border of that basin, and even overflowed a considerable part of Aberdeenshire, spreading southward until it met those streams which, proceeding from the Grampian Mountains, moved eastward along the valleys of the Dee and the Don. No part of the surface, therefore, escaped abrasion by the ice; and no remnant of pre-Glacial Tertiary deposits has hitherto been found in any part of the area, even in those spots where one would have thought that they might have been most likely to be preserved. Neither has any trace been obtained of the mammalian fauna which inhabited England during the inter-Glacial Period. No remains of the Mammoth, not even a tooth or a tusk, have been met with in any of the railway-cuttings or other excavations (so far as I am aware), although such have been found in Ayrshire and in the Basin of the Forth. One of the most interesting features in the Glacial Geology of Aberdeenshire is the Red Clay which occurs along the eastern coast of that county. Some account of it