the action of fire.[66] The same authors present the following section of a mound examined by them at Mound City, near Chillicothe, Ohio, which is a fair sample of the usual stratification observed in altar mounds.[67] The altar which this mound contained was a parallelogram measuring 8 × 10 feet at its base and 4 × 6 feet at its top. It was only eighteen inches in height, and contained a basin with a dip of nine inches. In this basin were found fine ashes, fragments of pottery and shell beads. A reference to the figure shows that the sand-stratum is semicircular, with its extremities resting on the outer sides of the altar. The skeleton shown in the figure designates a point three feet below the apex of the mound where two well-preserved skeletons were found. The strata were disturbed for their burial evidently at a considerable period after the construction of the mound. This is a fair example of the “intrusive burial” practised in the mounds by Red Indians. The same authors found some of these altars rich in relics; one especially in the vicinity of the above-described mound contained nearly two hundred pipes carved in stone. Also a considerable number of pearl and shell beads and copper ornaments covered with silver. It is quite probable that the copper was from their Lake Superior mines, as they alone are known to yield deposits of silver with copper. The same peculiarity was observed with reference to the copper ornaments and implements found in the Marietta works. The pipes secured in this mound were much calcined by heat, and considerable copper had been fused in the basin of the altar. In some of the mounds examined large collections were obtained, and in some instances, articles made of obsidian, which it is believed could be procured nowhere nearer than the Mexican mountains of Cerro Gordo, or the region west of the Rocky Mountains.[68] [Illustration: Pestles and Mullers. (Nat. Mus.) Surface Finds.] [Illustration: Section of Altar Mound. (After Squier and Davis.)] [Illustration: Vase from an Ohio Mound.]