The depth at which some accumulations occur, overlaid by the growth of the so-called primeval forest, points to them as contemporary with, if not in some cases older than, the earthworks of the Mound-Builders. The extent, indeed, to which some are overlaid by subsequent accumulations suggests a remote era. In 1853 Mr. Sellers first visited the site of one of those ancient work-yards, on the northern bank of the Saline river, about three miles above its junction with the Ohio. The region was then covered with dense forest, with the exception of a narrow strip along the bank of the river, which had been cleared in connection with recently opened coal works. But at a later date, in sinking a cistern, about 200 yards from the river bank, the excavation was made through a mass of flint chips. Subsequently heavy rains, after ploughing, exposed some spears and arrow points. “But it was not until the great flood of the winter of 1862 and 1863 that overflowed this ridge three or four feet with a rapid current, that the portion under cultivation on the river bank was denuded, exposing over six acres of what at first appeared to be a mass of chips or stone rubbish, but amongst it were found many hammer-stones, celts, grooved axes, cores, flakes, almost innumerable scrapers and other implements, and many tynes from the buck or stag, all of which bore evidence of having been scraped to a point. On exposure to the air they fell to pieces.” The actual site of the quarry appears to have been subsequently identified. “The greater number of cores, scattered flakes, finished and unfinished implements, are of the chert from a depression in a ridge three miles to the south-east, where there are abundant indications of large quantities having been quarried.” But the same great work-yard of the ancient Mound-Builders furnished evidence of other sources of supply. Mr. Sellers noted the finding “a few cores of the white chert from Missouri, and the red and yellow jasper of Kentucky and Tennessee,” but he adds, “the flakes of these have mostly been found in nests or small caches, many of which have been exposed; and in every case the flakes they contained were more or less worked on their edges; whereas the flakes from the neighbouring chert preserved their sharp edges as when split from the mass. These cache specimens with their worked serrated edges would, if found singly, be classed as saws or cutting implements. But here where found in mass, evidently brought from a distance, to a place where harder chert of a much better character for cutting implements abounds, they tell a different story.” The material was better adapted for the manufacture of certain classes of small implements much in demand, and the serrated edge is simply the natural result of the mode of working of this species of chert and of the jasper.