Measured By Barry Perlmutter, June 1970; Permian System,Wreford Limestone -- Chase Group,Three Mile Limestone Member,Limestone, gray, massive, chert nodules,Shale, dark gray, massive, crinoid columnals, other shell hash,Limestone, light gray to tan, massive, ostracodes present,Shale, dark gray, thin-bedded, no megafossils, base covered,Total thickness of section,