Historical:Battery Rock Sandstone Member
M. E. Hopkins and J. A. Simon
The Battery Rock Sandstone Member of the Caseyville Formation (Cox, 1875, p. 204) is named for Battery Rock, a bluff of massive sandstone on the west bank of the Ohio River in Hardin County.
The type section is Battery Rock, on the west bank of the Ohio River in Hardin County (26, 11S-10E).
The Battery Rock is correlated with the lower Caseyville conglomerate, or Kyrock Sandstone Member, of western Kentucky and with the lower part of the Mansfield Sandstone of Indiana.
Extent and Thickness
The Battery Rock Sandstone, a prominent bluff-forming unit (fig. P-3A), is very well developed in Gallatin, Hardin, and Pope Counties, where it is 50-100 feet thick in a large area. It is also as much as 100 feet thick in the western part of the southern Illinois outcrop belt, but there it is more lenticular. Along the southwestern side of the Illinois Basin, the sandstone extends only as far north as Randolph County. In the subsurface to the north and northeast of the outcrop belt, the Battery Rock is difficult to trace because several other thick sandstone units occur in the lower part of the McCormick Group.
The Battery Rock is generally medium-grained sandstone, but at places it becomes coarse; almost everywhere it contains scattered quartz granules and pebbles, which in places form conglomerate beds. Although the Caseyville sandstones have been called conglomerates, the term "conglomeratic" is more appropriate.
COX, E. T., 1875, Geology of Gallatin County: Geological Survey of Illinois, v. 6, p. 197-219.
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