832 J. A. BOWNOCKER 



Logan shales =shales (unnamed) 



Logan sandstone — Salt sand 



Mountain limestone 



Losran conglomerate V =', 



b D \ Big Injun series 



The limestone just named, and which is known also as the 



"Big lime," has a maximum thickness in this state of iio feet. 



It is a light-colored, hard, massive rock, free from oil and gas 



except along its margin, where the formation becomes broken 



and the layers of limestone are intercalated with sandstone. The 



formation is wedge-shaped with the apex to the northwest. It 



is limited to the eastern half of Washington and Monroe counties, 



and the southeastern corner of Belmont. To the west and north 



its place is occupied by shales and sandstones. The formation 



divides the Logan group into two unequal parts, and serves as a 



guide-post to the driller. 



T/ie Big Injun series. — This consists of the following 



members : 



Slate - - o- 20 feet 



Keener sand - -0-60 



Slate - - 0-25 



Big Injun sand 0-175 



Slate - - o- 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 is 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 considerably in texture, 

 but is usually coarse and open, sometimes conglomeritic. The 

 sand was named from the Keener farm near Sistersville, West 

 Virginia. 1 It is an important source of oil in Monroe and 

 Washington counties. The sand is separated from the under- 

 lying Big Injun by a bed of slate. Sometimes the latter is want- 

 ing, 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 



1 West Virginia Geological Survey, Vol. I, p. 357- 



