thickness, indolently basking in the sun-beams, or quietly cooling after exertion in the limpid wave—and these enormous tusks, ready to release him at a bound, when attacked by the enemy beneath. The dinotherium existed during the miocene period, and constitutes an intermediate link between the tapir and the mastodon. It has left abundant remains in the basin of the Rhine, in Bavaria and Austria, and in several districts of the formation in France. The tertiaries have a wide geographical distribution, and cover a vast extent of superficial area. Stretching from the Rhone to the Danube, they are found in every part of central and southern Europe, along the Julian Alps, and over the interior of Italy, from Ancona to Turin. The eocene group is ascertained, from the character of its fossils, and especially by its nummulites and echinoderms, to extend from the Mediterranean, through Egypt, Asia-Minor, and Persia, to Hindostan, and there to occupy large regions forming the western and northern limits of British India. This enormous mass of tertiary strata was drifted into lakes or estuaries, whereby the mind is carried back to a period when Europe was chiefly lacustrine, and all these countries eastward were as yet submerged in their waters. What explanation can geology give of their elevation to the surface? A scene of volcanic agency, now and _before_ the modern epoch extinct, remains to be noticed, which in part at least will furnish a probable solution of the changes then in operation or completed.