J. P. MacLean, A Manual of the Antiquity of Man
“ The Glacial Epoch, that has puzzled the mind of both the geologist and the astronomer, is a guide-post where he may not only look both ways, but also estimate the length of ages and number the years of man. Nothing, then, is of more importance, in this investigation, than an understanding of the condition of the earth prior to the glacial, and the knowledge of the date and length of this epoch.For untold ages the earth, to all appearance, had been preparing itself for the reception of man. ”
