Their statement with respect to the discovery of plaster of Paris upon one or more of the islands in the vicinity of Michilimackinac, to which the Indian title has not been extinguished, is correct. Specimens of this plaster have been brought here, and it is reported, by competent judges, to be of the best and purest kind. The quantity is stated to be inexhaustible, and, as vessels generally return empty, or nearly so, from the upper lakes, it could be transported to any part of Lake Erie at a trifling expense. I have great doubts, however, whether it would be proper for the Government to grant any permission to remove this plaster until the Indian title to the land is extinguished. The power of granting permission for that purpose is not given in the "act to regulate trade and intercourse with the Indian tribes, and to preserve peace on the frontiers," and appears, in fact, to be inconsistent with its general spirit and objects. To authorize these gentlemen to negotiate with the Indians for such a permission, is contrary to the settled policy which has always been pursued by the United States. I know of no case in which individuals have been or should be permitted to hold any councils with the Indians, except to procure the extinction of their title to lands, claimed under grants from one of the States. The application here must be to the tribe, because in all their land there is a community of interest, which cannot be severed or conveyed by the acts of individuals. But, independent of precedent, there are strong objections to this course in principle. If private persons are authorized to open such negotiations for any object, the Government will find it very difficult to procure from the Indians any cession of land upon reasonable terms. Were these islands the property of the United States, I think it would be very proper to permit the plaster upon them to be removed by every person making application for that purpose. The supply being inexhaustible, the agricultural interest would be greatly promoted by such a measure, and the dependence upon a foreign country for this important article would be removed. I therefore take the liberty of recommending that a cession of these islands be procured by the United States from the Indians. I presume that this may be done without the payment of any annuity to them, and without any expense, except, perhaps, a few trifling presents. The plaster would then be at the disposal of Government, and its free distribution, under such regulations as might be adopted to prevent disputes between the adventurers, or a monopoly by any of them, would be equally proper and beneficial. Very respectfully, sir, I have the honor to be Your most obedient servant, LEWIS CASS. Hon. JOHN C. CALHOUN, _Secretary of War_. V. Extract of a letter from the Secretary of War to Governor Lewis Cass, dated April 5, 1820.