In ‘The East,’ that wonderful cradle of the human race, towards whose sunrise we turn to find the dawn at once of Civilization and Romance, Nature exhibits herself in all the exuberance of her vitality, both of plant and animal. The summer and the rainy season unite, with no intervening period of spring and autumn. Seasons, like days, spring suddenly into full-blown development. Night is succeeded by day without dawn, and day by night without the lingering; hues of eve.

Sp. Chars.— Shell ovato-elliptical, or suborbicular, slightly convex in the median line, Flattended towards the margin; ears small, pointed, depressed, tringular, subequal, conate, their apices elevated above the level of the general periphery of the shell, both separated from the body of the shell, with their outer edges convex; umbones simple, straight, and pointed; muscular impression large, and situated near the beaks and posterior margin; shell thin and delicate; surface ornamented with numberous close, fine, concentric lines.

An ordinary glacier descends in virtue of the slope of its bed, and, as a general rule, it is on this account thin at its commencement, and thickens as it descends into the lower valleys, where the slope is less and the resistance to motion greater. But in the case of continental ice, matters are entirely different. The slope of the ground exercises little or no influence on the motion of the ice. In a continent of one or two thousand miles across, the general slope of the ground may be left out of account; for any slight elevation which the centre of such a continent may have will not compensate for the resistance offered to the flow of the ice by mountain ridges, hills, and other irregularities of its surface. The ice can move off such a surface only in consequence of pressure acting from the interior. In order to produce such a pressure, there must be a piling up of the ice in the interior; or, in other words, the ice-sheet must thicken from the edge inwards to the centre. We are necessarily led to the same conclusion, though we should not admit that the ice moves in consequence of pressure from behind, but should hold, on the contrary, that each particle of ice moves by gravity in virtue of its own weight; for in order to have such a motion, there must be a slope, and as the slope is not on the ground, it must be on the ice itself: consequently, we must conclude that the upper surface of the ice slopes upwards from the edge to the interior. What, then, is the least slope at which the ice will descend? Mr. Hopkins found that ice barely moves on a slope of one degree. We have therefore some data for arriving at least at a rough estimate of the probable thickness of an ice-sheet covering a continent, such, for example, as Greenland or the Antarctic Continent.

A Glance at the map stows that within a short distance of the town of Nottingham there are Coal-measures, Permian, Bunter, keuper, and Lias rocks. A paper therefore on the district must of necessity be somewhat lengthy, but perhaps of all the greater interest as dealing with the border-land of the Palæozoic and Mesozoic epochs. The generally supposed unconformability between the Permian and Triassic rocks does not appear to exist in this area; while that between the Permian and the Coal-measures is very considerable.