The geology of Centre County - D'Invilliers, Edward V. 1857-1928; Lesley, J. P. 1819-1903 (Board of Commissioners for the Second Geological Survey, 1884)
Karten-Beilage: "Centre County" (1 Blatt)
Außerdem enthalten: Analysis of Nittany Valley iron ores and limestones / by Dr. F.A. Genth (S. 385-394); Analyses of limestones / by Otto Wuth (S. 395); Mining methods / by J.W. Harden (S. 396-400)