Indiana Natural Gas Field. — Leverett- 19 
counties there is evidence of a minor anticlinal beneath which 
gas is found, while it is wanting in a narrow belt on the east 
between this productive area and the main gas field. Tipton 
lies in the unproductive belt, and the altitude of the Trenton 
here is some 35 feet lower than at productive wells five miles 
east or ten miles west from the city. This anticlinal appears 
to extend south to Sheridan and Joliet in Hamilton county 
and perhaps connects with the main field in the southern part 
of the county. We have no records to prove the extension of 
this anticlinal farther north than Kempton in western Tipton 
county. 
Exceptional loells. — At Oakland, in northeastern Marion 
county, gas is found in the Trenton at 210 feet below tide, or 
about 100 feet lower than in adjacent wells, and below the level 
at which water usually occupies the rock. The record of the 
boring was kept by the secretary of the gas company and ap- 
pears to be thoroughly reliable. This forms one of those puz- 
zling exceptions which arise under nearly every rule. Anoth- 
er exception, equally puzzling, occurs at Auburn, in DeKalb 
county. The altitude of the Trenton is about 150 feet lower 
than at Garrett, a village five miles west from Auburn. No gas 
was obtained at Garrett, but a well estimated to furnish 1,500,- 
000 cu. ft. per day was obtained at Auburn, The following 
rule laid down by Prof. Orton and found applicable nearly 
everywhere else apparently fails here. " The gas and oil are 
gathered in the arches of the Trenton if such there are. In 
default of arches the high-lying terraces are made to serve the 
same purpose, but the one indispensable element and condi- 
tion of all accumulation is relief." ' Prof. Orton explains the 
occurrence of gas at Bryan, Ohio, at an elevation 180 feet 
lower than that at Auburn, Indiana, as due to a minor eleva- 
tion of the Trenton. In the same manner he explains its oc- 
currence at Oak Harbor and Tiffin. - The only elevation we 
have discovered at Auburn and Bryan is that of a monoclinal 
rising from east to west. It is possible that at (larrett where 
the altitude seems to favor gas accumulation the texture of the 
rock is such as to exclude the gas. 
Diiference in altitude of saltwater line in Indiana and 
Ohio.— There is a marked diff'erence in the altitude of the salt 
^ Geology of Ohio; vol.vi, p. 309. 
■^ Geology of Ohio ; vol. vi, p. 310. 
