01044cam a22002651 4500 gs 40000143 DLC 20260227111345.0 780829s1939 pauab b s000 0 eng c gs 40000143 (OCoLC)4175448 U.S. Geol. survey. Library PU DLC TN24.P4 A7 TN24.P4 S82 Copy 2. Stone, Ralph W. (Ralph Walter), 1876-1964. The minerals of Pennsylvania: Non-metallic minerals, by R. W. Stone. Harrisburg, Pa., Department of Internal Affairs, Topographic and Geologic Survey, 1939. 50 p. incl. illus. (map) tables. 23 cm. Bulletin M, 18-C At head of title: Pennsylvania Geological survey, Fourth series With Ashley, G. H. The undeveloped mineral resources of Pennsylvania. 1933. (Bulletin M18-A) Bibliographical footnotes. Mines and mineral resources Pennsylvania. Non-metallic minerals--Pennsylvania. 27626 27626