[31]. It is this destruction of the stratified rocks which makes it so difficult to detect the marks of former glacial epochs, and which has led to such prevailing misconceptions regarding the evidence which we ought to expect of those epochs. See paper read before the Geological Society, “On Prevailing Misconceptions regarding the Evidence which we ought to expect of former Glacial Periods,” January 23, 1889.
[32]. Physical Geography, p. 94.
[33]. Quart. Journ. of Science, July 1877; Climate and Cosmology, chap. xvii.
[34]. Mem. Geol. Survey of Lancashire, 1862.
[35]. Mem. Geol. Survey of Great Britain, vol. iii.
[36]. Memoir to Sheet 32, Geol. Survey Map of Scotland.
[37]. Nature, vol. xiii. p. 390.
[38]. Explanation to Sheet 15, Geol. Survey Map of Scotland.
[39]. I have been informed by Mr. Peach that since the above was written additional light has been cast on this immense fault. It has been found, he says, that the fault consists of two sub-parallel branches, the more southerly of which has the effect of bringing the rocks of the Upper Silurian age against the Lower Silurian beds. The northern branch brings the upper division of the Lower Old Red Sandstones, in turn, against the Upper Silurian rocks. This, Mr. Peach remarks, does not in the least invalidate the reasoning as to the amount of material removed by denudation from this region in the time specified. In fact, it shows, he says, that a greater amount must have been removed than was at first suspected.
[40]. Jukes’s and Geikie’s Manual of Geology, p. 441.