52 ABORIGINAL MONUMENTS
was taken. These excavations are often ten or fourteen feet deep, and occupy acres in extent. It is possible the late, as well as the more remote, races worked these quarries. Like the red pipe-stone quarry of the Coteau des Prairies, this locality may have been the resort of numerous tribes,— a neutral ground where the war hatchet for the time was buried, and all rivalries and animosities forgotten.
One description of knives, found in the mounds, is ilustrated in the following engraving, which also exhibits the absolute identity that sometimes exists between the remains of widely separated people, and how, almost as it were by instinct, men hit upon common methods of meeting their wants:
No. 1 is of flint, from a Scandinavian barrow; No. 2 is of hornstone, from a mound in Ohio; and No. 8 is of obsidian, from the pyramids of Teotihuacan, in Mexico. They are all made in a like manner, by dexterously chip- ping off thin, narrow pieces from blocks of the various minerals mentioned, all of which break with a clear, con- choidal fracture and sharp cutting edges. Clavigero states that, so skillful were the Mexicans in this manufacture, that their workmen produced a hundred per hour. It was with knives of this kind that the bloody sacrifices of the Aztecs were performed.
In the manufacture of pottery, as has already been intimated, the mound-builders attained a considerable
