PREHISTORIC JASPER MINES. 665 



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 min- 

 ing at successive times, or, as seemed probable in one case, in re- 

 ducing 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 



FIG. 3. PART OF 6, 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 toil- 

 er's perseverance, challenged by this glimpse of his tools, increased. 

 Still, even granting all the pits a depth far beyond their appear- 

 ance, we little suspected the immense amount of work done, until 

 the arrangement of layers in our shaft, the scattered bits of char- 

 coal, the belts of stone-chippers' refuse, and the five distinct fire 



