There are other distinguishing characteristics in the ore even of closely adjacent mines, of so marked a nature that an expert has no difficulty in determining the locality of the mine, or even of the mine itself, from the appearance of the ore. Although scarcely within the scope of the present remarks, it is worthy of note that serpentines of an ornamental character are very abundant in Canada; some very beautiful specimens of which were recently shown in London, at the late Colonial and Indian Exhibition at South Kensington. Many of these contain small quantities of chromium and nickel, and are associated with soapstone, potstone, dolomite, and magnetite. A band of limestone also occurs at Templeton containing masses of a light-coloured translucent serpentine. These, however, beautiful as they are, do not at this moment specially concern us, as none of them contain asbestos in workable quantities, the stone being entirely of an ornamental character. They are exploited with some success by the Canadian Granite Company of Ottawa, and are used by them for monuments, mantelpieces, vases, and such like. One would certainly think that their importation into England would meet with success, seeing that there is always a demand here for fine marbles and stones for architectural and other purposes. Sir William Logan says: "Les serpentines, dans toute l'étendue de leur gisement, fournissent de très-beaux marbres vert-de-mer souvent ressemblant au vert antique." THE THETFORD GROUP OF MINES. Although the existence of asbestos in Canada, in one at least of the above-mentioned localities, was known to geologists for many years prior to 1877, it was not until the autumn of that year that a mine was discovered which proved to be of any commercial importance. This was first found by a farmer, named Fecteau, in the township of Thetford; and, true to its reputation, Thetford has continued to be the head-quarters and main source of the supply ever since. This, the first regular Canadian mine, was opened up in 1878 by Messrs. Johnson and Ward. The demand at first for the produce of this mine was exceedingly limited; indeed, great difficulty was experienced in finding a market at all. The output the first year was only about fifty tons; but the great value of the mineral being soon ascertained, exploration on the serpentine belt in this neighbourhood was prosecuted on an extensive scale, which resulted in asbestos being found in workable quantities over a very considerable area.