- Philadelphia: University of Pennsylvania Press, 1944.
- cloth, dust jacket.
- xiv, 170 pages.
Price: $65.00 other currencies
Order Nr. 28387
B1-711. First edition. With a number of illustrations including one by John Swientochowski. Information on Dr. Joseph Leidy, Francis Jordan, Hilborne Cresson and John Wigglesworth. Signed by the author on the title page. Spine of jacket is spotted and is price clipped.