that their death could not in all probability have long taken place. As the animals themselves are known to be existing species, it is indeed probable that this bed is still in a state of increase, however tedious and imperceptible the process may be.
Here then we have a fact which presents us with another modification of those strata which owe their origin to the action of living animals, or to the accumulation of their remains. It has always been known that marine animals acted an essential part in the production of the secondary, and even the latest of the primary, (or transition,) strata. It has lately been shown that considerable deposits and large beds of rock have also in former times been produced by testacea inhabiting fresh waters. But it has never been suspected that similar deposits could be formed on dry land. That such is the case here, is sufficiently evident from the angle of acclivity on which this bed is formed, on a surface which has assuredly undergone no alteration of its position since its formation, or at least since the formation of the granite. The fact itself is much too insulated and too narrow to admit of any generalization, or to justify us in supposing that similar formations might have taken place in a more ancient state of the globe. Else speculative minds might conceive that of the numerous elevated and apparently displaced strata which are now found containing organic remains, of which, not only the species, but the very genera as well as habits are unknown, some at least might have been derived from land animals, whose remains were converted into rocks in the very places where they now exist. Should causes with which we seem but very imperfectly acquainted at present, hereafter convert the marle bed now described into a rock, and all traces of its recent formation disappear, a circumstance at least within the limit of possibility, assuredly future geologists would
