296 The America it Geologist. NuviMiiber, is9d 
shaly la3'ei-s abound in calcareous replacements of various 
small fossil species, broken crinoid stems chiefly predominat- 
ing. These are so abundant in places as to give one the ini- 
pression of a highly fossiliferous formation. 
At the base of the shaly limestone there occurs a deposit of 
limestone a few feet thick, having a similar appearance on 
exposed surfaces, but which differs from that above in being 
slightly heavier-bedded, less shaly in striicture and composi- 
tion, and in having a distinctlv granular texture. This latter 
feature is due to its consisting almost exclusively of the dis- 
severed parts of crinoids. These are closely packed as in th-e 
Burlington limestone, bat it differs from that formation in 
being composed of the debris of smaller species, and hence the 
grain is much liner. Moreover, while the bulk of the rock is 
of a light gray and white color, certain species of crinoids 
seem to be tinted brown and buff', and these give to the rock 
a speckled appearance. This rock, then, is a highly fossil- 
iferous limestone ; and, if the base of the Kinderhook forma- 
tion is rightly placed over the Eureka shale, it must be of 
Devonian age. 
Occurring at the base of the Devonian strata in this region, 
and overlying the dolomites of the Ozark series, is the basal 
sandstone. This is a very thin but rather peculiar stratum of 
(juartz sand, strongly cemented with calcareous matter. The 
grains of sand vary in size from exceedingly tine to moder- 
ately coarse, and, in addition to the transparent quartz, man}- 
irregular j)articles of chert, white, and of other colors, derived 
from the cherts of the Ozark series, occur. The most curious 
of the contained minerals consists of small subangular parti- 
cles of a hard black quartz, which I have been unable to locate 
anywhere in the Ozarks, although it is possible that it maybe 
a common chert modified by some process to an opaque black 
color. Small particles of iron pyrites, besides limonitic stains, 
are present in the deposit and aid in giving it a color varying 
from bluish gray through light brown to a very light gray. 
At the ( 'orner cave in Barry county, where it is best devel- 
oped and attains a thickness of about one foot, this sandstone 
is of a white color, cemented by silica, \evy hard, and grading 
into an 0(»litic chert. 
