“ The mass of sea-water in the depth of the basin is either unaffected by the seasonal changes in surface temperature, which in Norway penetrate no deeper than 200 fathoms, or else, as in Loch Goil, the fresher film of surface water responds quickly to seasonal changes, while the heat of advancing summer penetrates so slowly to the depth of the basin that it takes six months to reach the bottom, arriving there in winter. ”

“ But investigations in such regions as the Rocky Mountains and the Yosemite Valley, where there is frequently a “reversed grade” similar to that near the seaward end of rock basins and fjords, seem to show, in some cases at least, that such a formation may be due to the “gouging” effect of a glacier coming down the valley which it constantly deepens where the ice pressure and the supply of eroding material are greatest. ”

“ They differ entirely from an estuary in the fact that they are bounded seawards by a rocky sill, covered by shallow water, and they deepen inland for some distance before the bottom again curves up to the surface. ”