The Pennsylvania geological survey;  administrative report, 
by Geo. H. Ashley. 
 - Harrisburg, Pa.,  Dept. of internal affairs, Topographic and geologic survey,  1931. 
 - 38 p.  illus. (map.)  23 cm. 
<br/><br/> At head of title: Pennsylvania geological survey, fourth series. 
<br/><br/><label>LCCN: </label>gs 31000068  
<br/><br/><label>LC Class. No.: </label>QE157  / .A315 
<br/><br/><label>Dewey Class. No.: </label>557.48