210

THE OLD BED SANDSTONE.

was first setting in, the wind had blown from off the northernor southern shora

But whence these abrupt precipitous hills that stud thelandscape, and form, in the immediate neighbourhood of thecity, its more striking features ? They belong—to returnto the illustration of the twice-frozen lake—to the middleperiod of thaw, when the ice broke up ; and, as they are com-posed chiefly of matter ejected from the abyss, might havecharacterized equally any of the other formations. Theirvery striking forms, however, illustrate happily the operationsof the great agencies on which, in the secondary and transi-tion deposits, all the peculiarities of scenery depend. Themolten matter from beneath seems to have been injected, inthe first instance, through rents and fissures among the car-boniferous shales and sandstones of the district, where it laycooling in its subterranean matrices, in beds and dikes, likemetal in the moulds of the founder ; and the places which itoccupied must have been indicated on the surface but bycurves and swellings of the strata. The denuding power thencame into operation in the form of tides and currents, andground down the superincumbent rocks. The inj ected masses,now cooled and hardened, were laid bare; and the softerframework of the moulds in which they had been cast waswashed from their summits and sides, except where longridges remained attached to them in the lines of the current,as if to indicate the direction in which they had broken itsforce. Every larger stone in a water-course, after the torrentfed by a thunder-shower has just subsided, shows, on thesame principle, its trail of sand and shingle piled up behindit. The outlines of the landscape were modified yet furtherby the yielding character of the basement of sandstone orshale on which the Plutonic beds so often rest. The base-ment crumbled away as the tides and waves broke against itThe injected beds above, undermined in the process, and with