Page:The Zoologist, 3rd series, vol 1 (1877).djvu/464

438 northward, owing to the difficulties encountered in finding sufficient spaces of open water when the vessels were stationary, I should not have ventured to place my views in such direct opposition to those announced by Dr. Jeffreys and Mr. Smith.

The examination, however, of the recent sea-beds, which extend from the present sea-margin to a height of not less than a thousand feet, afford additional proof of the correctness of my views. These beds are being deposited at the present day under precisely the same physical conditions as those now elevated above the sealevel, which give satisfactory evidence that the molluscan fauna of the past, represented by these post-tertiary deposits, is precisely that now existing in the adjacent sea. At least forty or fifty spots in Grinnell Land and Hall Land, where these beds occur, were carefully examined by independent observers, especially by Mr. Hart, Dr. Moss, Lieut. Parr, Lieut. Egerton, and myself; the sands and mud were also submitted frequently to microscopical investigation. The results of these independent examinations may be briefly summarised as follows:—Four species of Conchifera were very generally distributed as fossil forms, usually they occurred in very considerable numbers; these were Pecten grœnlandicus, Astarte borealis, Saxicava rugosa, and Mya truncata. The fossil Gastropoda were excessively rare; after days of searching we met with only a few specimens of Trichotropis borealis, one or two of Buccinum hydrophanum, a single Trophon clathratus, and a few Pleurotoma tennicosta, P. exaruta, and P. Trevellianum. Our dredgings showed that a nearly similar disproportion existed in the number of individuals between the recent Conchifera and Gastropoda. I deem, therefore, that our knowledge of the molluscan fauna of the area under discussion was acquired by us under most favourable circumstances, large deposits of recentlyemerged sea-bed were laid open to our investigations, and the result showed a remarkable correspondence between their fauna and that of the neighbouring sea. The not unnatural conclusion I have arrived at is that the recent and post-tertian faunas combined, show very accurately the present condition of the molluscan fauna of Smith Sound and northward to the eighty-third degree.

I can well understand, as Dr. Gwyn Jeffreys writes, that he has collected in the "so-called glacial" and raised sea-beds in Great Britain, Scandinavia, and Canada, in two or three hours, a greater number of fossil species than those procured in the Expedition,