The geology of Huntingdon county.
By: By I.C. White and other assistant geologists. Edited by J.P. Lesley.
Contributors: Lesley, J. P. 1819-1903 ed.; D'Invilliers, E. V. 1857-1928; Ewing, A. L.
Series: Pennsylvania. Geological Survey, 2d. Report of progress -- T3; Report of progress (Geological Survey of Pennsylvania) -- T3.
Publisher: Pub. by the Board of Commissioners for the Second Geological Survey
Published: 1885
Place of publication: Harrisburg
Language: eng
Number of pages: 471
Subjects: Geology -- Pennsylvania -- Huntingdon County.
Notes: Two maps and two diagrams folded in pocket.

"On the chemical erosion of the Nittany Valley limestone, by Prof. A.L. Ewing": p. 451-454.