Two widely diverse opinions are held among glacialists in seeking to explain how the ice-sheet transported its drift and left it amassed in its various deposits. One supposes that the drift was carried forward chiefly beneath the ice, being pushed or dragged along in contact with the land; the other, that it was in large part, or perhaps nearly all, englacial during its transportation, being enclosed in the lower part of the slowly moving ice-sheet. According to the latter view, which my observations lead me to accept, the drift after its journey in the ice was thence deposited not only in the knolls, ridges and hills called kames, eskers, moraines, and drumlins, but also in low and smooth or only moderately undulating tracts of till. The opinion first noted regards the ice-sheet as almost destitute of enclosed drift, excepting very near its base; while the second considers the bottom . . .