STATE GEOLOGIST. Wa 
CHAPTER I. 
THE OIL AND GAS-PRODUCING ROCKS OF OHIO. 
These have great range stratigraphically. The Trenton limestone 
is the lowest, and the Monongahela formation, or the Upper Productive 
Coal Measures, the highest. Between these extremes a large number of 
formations exist, which produce oil or gas in commercial quantities. 
These rocks differ greatly in their chemical and physical properties. This 
chapter enumerates the producing formations, shows their position in 
the geological column of the state, and gives their most important physi- 
cal and chemical properties. 
THE PRINCIPAL DIVISIONS OF THE GEOLOGICAL SCALE IN OHIO, AND 
THE OIL- AND GAS-BEARING MEMBERS. 
( ( Goose Run sand 
| | Mitchell sand 
First Cow Run sand 
Coal measures 
| Macksburg 500-foot sand 
Second Cow Run sand 
Salt sand 
| Pottsville conglomerate 
Maxton sand 
Carboniferous 
‘ 
| : : ( Maxville limestone........ Mountain lime 
| ( Keener sand 
| ey RONeE 4 Logan group........... Big Injun sand 
| | | Squaw sand 
aM |. Berea grit 
MDE VOMIATIES (i. c) cia, Ae ete bs Vado sci cto veseie « ... Ohio shales 
f } Lower Helderberg sand 
PSHUNUDETEC OWA See A Aer ante Annee cere Me 
Clinton sand 
Ordoviciane sss. 1 is eC OORIEe Trenton limestone 
28. G. 
