If, however, the severance of the Mount from the mainland was the result, not of retrocession, but of the subsidence of the country,—a rival theory which Mr. Pengelly still admits as possible,—the former calculation would fail, and the only means of fixing the date of this severance would be supplied by the remains found in the forests that were carried down by that subsidence, and which are supposed to belong to the mammoth era. This mammoth era, we are told, is anterior to the lake-dwellings of Switzerland, and the kitchenmiddens of Denmark, for in neither of these have any remains of the mammoth been discovered. The mammoth, in fact, did not outlive the age of bronze, and before the end of that age, therefore, St. Michael’s Mount must be supposed to have become an island. In all these discussions it is taken for granted that St. Michael’s Mount was at one time unquestionably a “hoar rock in the wood,” and that the land between the Mount and the mainland was once covered by a forest which extended along the whole of the seaboard. That there are submerged forests along that seaboard is attested by sufficient geological evidence; but I have not been able to discover any proof of the unbroken continuity of that shore-forest, still less of the presence of vegetable remains in the exact locality which is of interest to us, namely between the Mount and the mainland. It is true that Dr. Borlase discovered the remains of trunks of trees on the 10th of January, 1757; but he tells us that these forest trees were not found round the Mount, but midway betwixt the piers of St. Michael’s Mount and Penzance, that is to say, about one mile distant from the Mount; also, that one of them was a willow-tree with the bark on it, another a hazel-branch with the bark still fat and glossy. The place where these trees were found was three hundred yards below full-sea mark, where the water is twelve feet deep when the tide is in. Carew, also, at an earlier date, speaks of roots of mighty trees found in the sand about the Mount, but without giving the exact place. Lelant (1533-40) knows of “Spere Heddes, Axis for Warre, and Swerdes of Copper wrapped up in lynist, scant perishid,” that had been found of late years near the Mount, in St. Hilary’s parish, in tin works; but he places the land that had been devoured of the sea between Penzance and Mousehole, _i.e._ more than two miles distant from the Mount.