TOWKE] ABORIGINAL FLINT QUARRIES 505 
the skull above the bottom near the center and to within 6 inches 
of the feet of those in the grave. The hole they made had par- 
tially filled up, but enough of a depression remained to catch con- 
siderable water, which, soaking down, softened such bones as it 
reached. 
ABORIGINAL FLINT QUARRIES 
The siliceous stone commonly called “flint ” is found in some of its 
forms in association with the limestone deposits in geological forma- 
tions of different epochs. 
There is a tendency on the part of geologists to restrict the name 
“flint” to that variety of the stone which occurs so plentifully in 
the chalk beds of western Europe, especially in England and France. 
Before the invention of percussion caps this was used to make a 
spark for igniting the powder in firearms. In large pieces it appears 
black, but in thin fiakes it more resembles smoked glass. It does 
not occur—at least it has not yet been discovered—in the Western 
Hemisphere, and geologists prefer, for distinction, to apply the name 
“chert ” to that which is found here. However, the popular term, 
derived from the former use of “ flints” for guns, has come into such 
common use that its status now seems to be firmly established. 
The European variety owes its origin mainly to spicules of sponges 
which flourished in the seas of the Cretaceous period; but, in America 
at least, most flint or chert, using the terms as synonymous, results 
from the life and activity of microscopic animal and plant life which 
flourished in shallow basins or depressions near the shore line of the 
ocean, partially inclosed by projecting land areas that would allow 
free access of the salt water but would shelter the little bay from dis- 
turbing waves and currents. Limestone also forms in these condi- 
tions, but is the product of larger forms of life which abstract lime 
from the sea water and convert it into supporting material, either 
as skeleton or as shell. The diatoms and animalcules secrete siliceous 
substance held in solution, in the same manner that mollusks and 
corals secrete lime, but the former, being infinitely smaller, the result- 
ing stone, when formed in clear water, is so close-grained as to appear 
homogeneous like glass or agate. The finer product is usually depos- 
ited in the deeper portions of the inlet, at some distance from the 
margin, beyond the line to which currents can transport sediment 
stirred up by wave action on the beach or the mud and silt carried 
down by streams flowing in. Nearer land, the chert, owing to the 
admixture of such foreign elements, becomes granular or porous, 
forming buhrstone or even assuming a spongy or cellular structure 
from the inclusion of shells and other mineral substances which are 
afterwards dissolved by the water and disappear, leaving cavities 
where they existed. In either case the chert thus formed may be 
55231 °—28——33, 
