THE OIL- AND GAS-PRODUCING ROCKS OF OHIO 833 



resembles the Keener. It is recognized in several counties in 

 southeastern Ohio, but is a producer of oil or gas in commercial 

 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 from Monroe county, but it is of 

 little importance even there. 



The Salt sand. — This is the highest of the sands of the Logan 

 group. It has a gray color, is moderately coarse, and nearly 

 always is charged with brine. Occasionally it contains a little 

 oil and gas, but it cannot be recognized as a producer of either. 



II. THE COAL-MEASURES. 



While a large number of strata belonging to the Coal-meas- 

 ures have been or are now sources of oil, comparatively few of 

 these have been important in a commercial sense. Generally the 

 sands are local, and cannot be traced over an area of more than 

 a fraction of a mile. Such sands usually have names, but because 

 of 'their small area and production they will not be further noticed 

 in this article. The most important sands of the Coal-measures 

 are the following : 



5. Goose Run sand. 



4. Mitchell sand. 



3. First Cow Run sand. 



2. Macksburg 500-foot sand. 



1 . Second Cow Run sand. 



The relative positions of sands I and 3 are shown by the fol- 

 lowing data taken from Centennial Well No. 6 at Cow Run : 



Thickness D f T h 'V^ 



of formation 



Pittsburg coal .... 1 foot 1 1 feet 



First Cow Run sand - - - 47 feet 325 

 Second Cow Run sand - 64 776 



The stratigraphical relation of sands 2 and 3 is shown by the 

 following record taken from Dunn Well No. 6, near Macksburg. 

 The well head is six feet below the Meigs Creek coal. 



