The succeeding anticlinal south only carries the Salina lime shales; but in the flank of the next ridge to the south the limestone shows in good condition, dipping steeply southwards and largely quarried for road purposes as well as lime burning for several hundred feet along the pike.
Limestone quarries.
At the Stratford quarry here about 60′ of good limestone is quarried and burned for farm and plaster purposes. The dip is about 50° to the southeast; therefore the good stone has a tendency to bury itself beneath the ridge.
At the Mt. Rock grist mill several massive beds are exposed in a section of limestone and lime shales aggregating nearly 350′ in thickness. The Oriskany sandstone south of this point is about 30′ thick and is too hard and cherty in character to be serviceable for glass purposes.
Logan Iron and Steel quarry. The most important quarry opened in the Lewistown limestone in this township is that of the Logan Iron and Steel Company, who obtain from it their furnace flux. This quarry is located immediately back of their furnace, and is situated geologically exactly in the synclinal basin, the rocks lying very flat at the opening and rising north and south from its center. All their furnace stone is obtained from the middle division of the Lewistown limestone, the formation being naturally divided here into three members: 1. An upper member, about 10′ thick; 2. A middle member of good pure limestone from 50′ to 60′ thick, and solely used for obtaining the furnace flux; 3. A lower member 20′ thick. The upper bed is very fossiliferous, and shows a high percentage of alumina and siliceous matter, the lower member is very siliceous. So that it may be said that all the good limestone is confined to the central member, about 60′ thick.
Mr. R. H. Lee, Jr., chemist, reports the following to represent the usual average character of this central member of the formation as a furnace flux, and only in respect of the silica, alumina, iron and phosphorus present in the raw limestone.
