SURELY Mr. Newberry has too quickly come to the conclusion with which his paper of February 16 (“Hypothetical High Tides”) terminates. I think if he reconsiders the matter he will still find that there is room for discussion. Has he fully taken into consideration the fact that at present, although in some places there are tides of thirty feet or more in height, notably where the waves roll in from the open ocean to some of the more or less confined bays or estuaries, on the contrary, in confined seas on the Mediterranean, Euxine, and Baltic, the tide is scarcely perceptible? This being the case, is it satisfactorily proved that the old Potsdam beach of which Mr. Newberry speaks was not deposited on the shore of such an inland sea, where, in despite of the fact that the oceanic tides might measure 200 feet or more, yet here I think the littoral zone might be comparatively quiet; at any rate sufficiently so to support both animal and plant life? I merely make this suggestion in the hope that somebody more able to deal with the subject than I am will continue the discussion.