524 ARCHEOLOGICAL INVESTIGATIONS—II [ETH, ANN. 44 
The bedded stone in this region is highly susceptible to both sub-~ 
aerial and subterranean erosion; the topography, in consequence, is 
very irregular. Sink-holes occur by thousands; in fact, the so-called 
“valleys”. are nothing but depressions from which the entire mass 
of limestone formerly occupying them has been carried away by un- 
derground drainage. One of these sinks, known as “Grass Valley,” 
is an irregular area about 8 miles long by 5 miles across, having an 
average depression of 100 feet below the surrounding rim. Most of 
the streams are bordered in portions of their course by vertical cliffs 
from 50 to 200 feet high, while smaller cliffs are numerous along the 
slopes, in places where no water is to be seen except in rainy seasons. 
Some of these cliffs are the borders or side walls of former caverns 
whose roofs have fallen in. 
The workable flint is by no means continuous over the entire 
space where it comes in view. The overlying rock is a solid, heavy- 
bedded limestone, and in the hills this made access to the flint strata 
impossible to the Indians; under such conditions they could only 
gather up the nodules along the hillsides where they were washed out, 
or dig slight pits which would soon fill up from the slopes above 
them. On the other hand, where disintegration and denudation had 
exposed the nodules to atmospheric influences they would become 
chalky or split up into angular fragments unfit for flaking. 
So it appears that the native flint worker secured his supply in 
three different ways. He gathered it in ravines as it washed out of 
the hills; he dug as far back as he could into the slopes where he had 
thus learned that it was to be found; and he dug shallow pits where 
the decay of the protecting limestone had left a coating of clay thick 
enough to preserve the flint in good condition. The pits were 
shallow because by the time the limestone was all gone there was 
not much clay left. 
The nodule-bearing stratum does not appear east of Buck Creek, 
unless in the highest hills; from here the dip is to the southwest at 
the rate of about 40 feet to the mile, which brings it to water level 
along Blue River. The solid blue variety appears, also, to be con- 
fined to an area about 10 miles in length along the strike of the rock 
and about 5 miles in breadth. It may exist beyond these limits; but 
if so, it has not been observed. 
On the left bank of Indian Creek, in Scott Township (NW. %4 
sec. 19, T. 4 S., R. 36 E.), on the land of 8. M. Mauck, nodules have 
been extensively quarried. An area of 5 or 6 acres is covered with 
small pits, none of them now more than 3 feet deep; leaves and 
trash were cleared out of two to a depth of 4 feet before reaching 
bottom. In one were found, at the bottom, fragments of antlers, 
so decayed that it could not be determined whether they had been 
