STATE GEOLOGIST. ~ 25 
counties, and the southeastern corner of Belmont. To the west and 
north its place is occupied in part at least by shales and sandstones. The 
formation makes the summit of the Lower Carboniferous, and serves as a 
guide-post to the driller. 
The Big Injun Series. —This consists of the following members: 
S1atage oe ees 0— 20 feet 
_ Keener sand ...... 0-— 60 
DBO ere eee cies 0— 25 
Big Iniun sand.... 0—175 
Slate Betts ote ee d0— 10 
Squaw sand ...... 0— 30 
From this it is seen that the group varies greatly. Sometimes it is 
little more than one great mass of sandstone, while at other times it 1s 
broken into a series of alternating beds of slate and sandstone. The Keener 
sand occasionally lies immediately below the Mountain limestone, but more 
often is separated from that rock by a few feet of shales. It varies- con- 
siderably in texture, but is, usually coarse and open, sometimes -conglom- 
eritic. The sand was named from the Keener farm, near Sistersville, 
West Virginia.’ It is an important source of oil in Monroe and Wash- 
ington counties. The sand is separated from the underlying Big Injun 
by a bed of slate. Sometimes the latter is wanting, and then the two 
sands run together and are conjointly called the Big Injun. The sand 
in question (Big Injun) is by far the thickest member of the series, but 
in other respects resembles the Keener.. ;It is. recognized in several 
counties in southeastern Ohio, but is a. producer of oil.or. gas in com- 
mercial quantities in Monroe and Washington counties only. To the 
west and north the formation becomes too broken to be a repository for 
oil or gas. Below the Big Injun, and separated from it by a thin bed of 
shales, there is occasionally found another layer of sand known as the 
Squaw. It is decidedly patchy, and never extends over large areas in this 
state. The best records of it are reported fron: Monroe county, but it is 
of little importance even there. 
II. THE COAL MEASURES. 
These include not only the formations containing seams of coal, 
but also several hundred feet of rock lying between the Sharon or No. 1 
coal andthe Mountain limestone. This is part of the great Pottsville 
conglomerate. For convenience the rocks of the Coal-measures will be 
divided into first, the Pottsville Group; second, the Coal Measures 
proper. Oa 
Pottsville Group.—This group of sands lies in the-lower part of the 
Pottsville conglomerate, that is, between the Sharon’or No. 1 coal and 
1West Virginia Geol. Survey, Vol. I, p. 357. 
