01021cam a22002651i 4500 gs 41000156 DLC 20260227111347.0 800825s1941 xx 000 0 eng c gs 41000156 (OCoLC)6651478 U.S. Geol. survey Lib. PLhS DLC premarc QE157 .A293 no. 126 Laird, Wilson Morrow, 1915- The upper Devonian and lower Mississippian of southwestern Pennsylvania / by Wilson M. Laird. [Harrisburg : 1941] 1 p. l., 23 p. : tables, diagrs. ; 23 cm. Pennsylvania. Bureau of Topographic and Geologic Survey Progress report 126 At head of title: ... Commonwealth of Pennsylvania. Dept. of internal affairs ... Topographic and geologic survey ... "Literature survey": p. 2-4. Geology Pennsylvania. Geology, Stratigraphic Devonian. Geology, Stratigraphic Mississippian. 27743 27743