beginning of geologic history does not the epoch of the old coast-line form! It is but a mere starting point from the recent period. Not a single shell seems to have become extinct during the last six thousand five hundred years! The shells which lie embedded in the subsoils beneath the old coast-line are exactly those which still live in our seas. [Illustration: Fig. 87. ASTARTE ARCTICA.] [Illustration: Fig. 88. TELLINA PROXIMA.] Above this ancient line of coast we find, at various heights, beds of shells of vastly older date than those of the low-lying terrace, and many of which are no longer to be found living around our shores. I spent some time last autumn in exploring one of these beds, once a sea bottom, but now raised two hundred and thirty feet over the sea, in which there occurred great numbers of shells now not British, though found in many parts of Britain at heights varying from two hundred to nearly fourteen hundred feet over the existing sea level. But though no longer British shells, they are shells that still continue to live in high northern latitudes, as on the shores of Iceland and Spitzbergen; and the abundance in which they were developed on the submerged plains and hill-sides of what are now England and Scotland, during what is termed the Pleistocene period, shows of itself what a very protracted period that was. The prevailing tellina of the bed which I last explored,--a bed which occurs in some places six miles inland, in others elevated on the top of dizzy crags,--is a sub-arctic shell (_Tellina proxima_), of which only dead valves are now to be detected on our coasts, but which may be found living at the North Cape and in Greenland. The prevailing astarte, its contemporary, was _Astarte arctica_, now so rare as a British species, that many of our most sedulous collectors have never seen a native specimen, but which is comparatively common on the northern shores of Iceland, and on the eastern coasts of Norway, within the arctic circle. In this elevated Scottish bed of the Pleistocene period I laid these boreal shells open to the light by hundreds, on the spot evidently where the individuals had lived and died. Under the severe climatal conditions to which (probably from some change in the direction of the gulf stream) what is now Northern Europe had been brought, this tellina and astarte had increased and multiplied until they became prevailing shells of the British area; and this increase must have been the slow work of ages, during which the plains, and not a few of the table lands, of the country, were submerged in a sub-arctic sea, and Great Britain existed as but a scattered archipelago of wintry islands. But in a still earlier period, of which there exists unequivocal evidence in the buried forests of Happisburgh and Cromer, the country had not only its head above water, as now, but seems to have possessed oven more than its present breadth of surface. During this ancient time,--more remote by many