Highway geology, Philadelphia to Pittsburgh Willard, Bradford 1894- creator text pau Harrisburg, Pa Department of internal affairs, Topographic and geologic survey 1939 monographic eng
print
2 p.l., 42 p. illus., 2 maps (1 fold.) fold. tab. 23 cm. by Bradford Willard. At head of title: Pennsylvania Geological survey, Fourth series. On cover: Commonwealth of Pennsylvania. Department of internal affairs. "References": p. 27-28. Geology Pennsylvania QE157 .W53 Bulletin G, 12 gs 39000356 U.S. Geol. Survey. Library 770602 20260227111345.0 gs 39000356