Page:Quarterly Journal of the Geological Society of London, vol. 35.djvu/190

140 places the stratum with the mammoth in his "Interglacial period." A second example of the discovery of mammoth in association with the Boulder-clays is that of a tusk found, at a depth of fifteen to twenty feet from the surface, by the eminent engineer Mr. Bald, at Clifton Hall, in the valley of the Forth, at the beginning of this century. A third instance is offered also by the remains at Chapel Hall, near Airdrie, in laminated sand under the "till." These cases are taken by Mr. Jamieson to prove that the mammoth lived in Scotland before Glacial conditions had set in in Northern Britain; and his conclusion seems to me to be probably true.

If, however, the true relation of the strata with mammoths in the above cases to the lowest Glacial deposits of Scotland be considered doubtful, the Preglacial age of the mammoth in Cheshire is definitely set at rest by the discovery made by Mr. Bloxsom in March 1878, in sinking a shaft for the new Victoria Salt Co. near Northwich. The travelling cylinder used in the operation cut through the fossil-tooth of "some gigantic animal," which was sent to me for identification. It proved, on comparison with remains in the British Museum, to be a fragment of the last lower true molar of the mammoth, left side, composed of the last seven plates with the talon, and measuring 5⋅5 inches long by 2⋅5 and 1⋅8 broad. From an examination of the matrix it had evidently been imbedded in a fine sand highly charged with dark carbonaceous particles.

The precise conditions of its discovery are shown in the following section (fig. 2), the details of which have been furnished by the kindness of Mr. Bloxsom. The tooth was found at a depth of sixty-five feet from the surface of the ground, in the sand No. 1, at the point marked A in the figure.

The overlying Boulder-clay, as may be seen from the horizontal geological section, sheet 64, made by Prof. Hull, extends without a break from Northwich to Aston; it reappears near Millington Hall, and extends, except where it is cut through by the river Bollin, under the middle-drift sand and gravel of Bowdon, and thence in a