The execution of such imitations also usually betrays their origin. The lines on the Lenape Stone are obviously cut with a metal instrument, making clean incisions, deepest in the centre and tapering to points--quite different from the scratch of a flint point. Shrewder fabricators than the unknown author of this one make use of flint points. Some of the Western "tablets" have been so inscribed. They may thus conceal their tools, but there are other resources for the archæologist. The surface of all stones undergoes a certain chemical change on exposure to the air, which is called by the French term _patine_. In many varieties, as flints, jasper, and hard shales, this affords a decisive means of discriminating a modern from an ancient inscription or arrow-head. It requires the use of the microscope and some practice, but with these most of such impostures can be detected. This does not exhaust the resources at the command of the antiquary to circumvent those who would practise on his love for relics of the past. But I have said enough to show that opinions on relics need neither be vague nor prejudiced. It is most desirable that the citizens of our Commonwealth should take an earnest interest in the collection of our aboriginal remains, and it is gratifying to learn that Bucks County is not behindhand in this direction. Respectfully yours, [Signed] D. G. BRINTON, M.D. From the Bucks County _Intelligencer_ of Sept. 6, 1884. Letter from Mr. H. Carvill Lewis, Professor of Mineralogy, Academy of Natural Sciences, Philadelphia. PHILADELPHIA, Feb. 19, 1884. CAPT. J. S. BAILEY: _Dear Sir_:--Upon careful examination I am convinced that the mammoth on the Indian tablet is a forgery, being copied directly from the drawing of a mammoth on a piece of ivory found in the cave of La Madeleine, Perigord, France. The tablet is genuine, but the drawing upon it is recent. Who do you think perpetrated this fraud? Yours, very truly, [Signed] H. CARVILL LEWIS. Letter from Dr. F. W. Putnam, Curator of the Peabody Museum of Archæology, Cambridge, Mass. CAMBRIDGE, March 17, 1884. DEAR MR. MERCER: