lying at an angle of scarcely twenty degrees to the strata in which they were imbedded. Their passage through the solid rock, therefore, cannot be estimated at less than fifteen to twenty feet, that is, a mass of sandstone of corresponding depth must have been formed, during the comparatively short period that trees of lofty stature were able to resist the destroying action of the elements, to say nothing of the chances of currents, hurricanes, and other agents breaking them in pieces. This _instantia crucis_ may be extended to every sandstone bed of the formation, and thus serve to exercise a salutary restraint upon the mind in its imaginary conceptions of the enormous periods of time required for the accumulation of the whole series. The carboniferous epoch was immediately succeeded by a period of great violence and of vast disturbance in the solid crust of the earth. Hence the broken inclined position of the coal strata, and the injection of so much igneous matter, forming often ridges and hills of considerable elevation. The new red sandstone, the overlying deposits, would share in all the activity of the time. A celerity of increase, on a scale of more rapid accumulation than existing causes could produce, must consequently fall to be admitted to the rocks of this family: so much, indeed, was the plutonic agency then in force, that the rock-salt and gypseous beds are ascribed to its influence. From this period downward, the formations are all of more contracted dimensions, the basins narrowing in superficial area to the upper tertiaries, which partake of the character of local rather than of universal deposits; while the evidences here are innumerable that, until the globe settled into its present form, and assumed its present arrangement of seas, continents, and mountains, the land and water were continually changing places, the crust and framework subject to constant upheaval. The Cordilleras and Himalaya constituted, in those days, the bed of the ocean. What law of nature was not in violent activity ere they attained their sublime altitudes! How many rivers changed their courses! how many mountains were washed to their summits! how many hills melted like wax at the voice of their Creator, amidst convulsions which swept the earth so repeatedly of its living tribes, and bared as often the bosom of the great deep!