The undeveloped mineral resources of Pennsylvania /
Ashley, Geo. H. 1866-
The undeveloped mineral resources of Pennsylvania / introduction by George H. Ashley. - Harrisburg, Pa. : Department of internal affairs, Topographic and geologic survey, 1933. - 16 p. : incl. tables ; 23 cm. - Pennsylvania. Geological survey, 4th (1919- ) Bulletin M18-A . - Bulletin M ; 18-A. .
At head of title: Pennysylvania Geological survey, Fourth series.
gs 38000043
Mines and mineral resources--Pennsylvania.
TN24.P4 / A7
The undeveloped mineral resources of Pennsylvania / introduction by George H. Ashley. - Harrisburg, Pa. : Department of internal affairs, Topographic and geologic survey, 1933. - 16 p. : incl. tables ; 23 cm. - Pennsylvania. Geological survey, 4th (1919- ) Bulletin M18-A . - Bulletin M ; 18-A. .
At head of title: Pennysylvania Geological survey, Fourth series.
gs 38000043
Mines and mineral resources--Pennsylvania.
TN24.P4 / A7