The upper Devonian and lower Mississippian of southwestern Pennsylvania Laird, Wilson Morrow 1915- creator text xx Harrisburg 1941] 1941 monographic eng
print
1 p. l., 23 p. : tables, diagrs. ; 23 cm. by Wilson M. Laird. 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 QE157 .A293 no. 126 gs 41000156 U.S. Geol. survey Lib. 800825 20260227111347.0 gs 41000156