The minerals of Pennsylvania: Non-metallic minerals,
Stone, Ralph W. 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.
gs 40000143
Mines and mineral resources--Pennsylvania.
TN24.P4 / A7
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.
gs 40000143
Mines and mineral resources--Pennsylvania.
TN24.P4 / A7