Page:Popular Science Monthly Volume 43.djvu/683

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665
PREHISTORIC JASPER MINES.

by one, must have scraped away the surrounding clay till the pits were made.

That fire had been extensively used on the surface there was no question, whether in the clearing away of underbrush for mining at successive times, or, as seemed probable in one case, in reducing the large fragments, and coloring yellow jasper red.

But far more interesting was it to find fifteen feet down in our shaft an oven designedly made of large blocks of coarse jasper, in the hollow of which rested a mass of charcoal and ashes. To be satisfied that the bowlders had been thus cracked and splintered by heat, it was but necessary to notice their reddened sides and gather up the fire-fractured fragments of all sizes in their cavities.

Several holes in the clay near the bottom were no more nor less than the perfect molds left by objects of wood long since rotted to nothingness, and these enabled us by pouring in plaster of Paris to recover the forms of a piece of sapling about two feet in length, and the fragment of a larger tree, both pointed at one end, and plainly showing the marks of the stone tools that had sharpened them. (See Figs. 1, 2, and 3.)

That one at least of these billets (Fig. 1, a) was intended for use in quarrying there could be no doubt; still less that a large disk

PSM V43 D683 Pointed log showing stone tool marks.jpg
Fig. 3.—Part of b, Fig. 1, enlarged, showing Stone Tool Marks.

of bluish limestone, chipped into the form of a heavy hoe, and well worn on its edges, if not a smaller fragment of quartzite, had been used as rough digging tools. (See Fig. 4, a, b.)

But as the pickaxe struck fire on the stones and glanced often impotently from the compact clay, our wonder at the ancient toiler's perseverance, challenged by this glimpse of his tools, increased. Still, even granting all the pits a depth far beyond their appearance, we little suspected the immense amount of work done, until the arrangement of layers in our shaft, the scattered bits of charcoal, the belts of stone-chippers' refuse, and the five distinct fire