In the case of the delta of Holland having extended so far northward, a subsidence of the land or rising of the sea, so as to form a passage for the waters round Britain, must have occurred. The derangement, at several places, of the fine wavy stratification of these carses, and the confusedly heaped-up beds of broken sea-shells, shew that some great rush of water had taken place, probably when Belgium was dissevered from England. Since the opening of the bottom of the gulf, the accumulation may have been undergoing a gradual reduction, by more diffused mud[69] being carried off from the German Sea into the Atlantic and North Sea, than what the former is receiving—the same process taking place here as has been occurring in the basin of the Tay. The large sand-banks on the Dutch and English coast,—in some places, such as the Goodwin Sands, certainly the heavier, less diffusible part of the former alluvial country, and portions of these alluvial districts being retained by artificial means,—bear a striking resemblance to the {381} sand-banks of the sea basin of the Tay—the less diffusible remains of the removed portion of the alluvium which had once occupied all that basin, and to the remaining portion of the alluvium also retained by artificial means. * * * * * Throughout this volume, we have felt considerable inconvenience, from the adopted dogmatical classification of plants, and have all along been floundering between species and variety, which certainly under culture soften into each other. A particular conformity, each after its own kind, when in a state of nature, termed species, no doubt exists to a considerable degree. This conformity has existed during the last forty centuries. Geologists discover a like particular conformity—fossil species—through the deep deposition of each great epoch, but they also discover an almost complete difference to exist between the species or stamp of life, of one epoch from that of every other. We are therefore led to admit, either of a repeated miraculous creation; or of a power of change, under a change of circumstances, to belong to living organized matter, or rather to the congeries of inferior life, which appears to form superior. The derangements and changes in organized existence, induced by a change of circumstance from the interference of man, affording us {382} proof of the plastic quality of superior life, and the likelihood that circumstances have been very different in the different epochs, though steady in each, tend strongly to heighten the probability of the latter theory.