Frank Cathcart Calkins (1878-1974) was a mapper, petrologist, and geologist. Collection consists of correspondence, primarily to Henrietta Mack Eliot, 1973-1974, regarding past trips to the Pacific Northwest while working for the U. S. Geological Survey, as well as letters concerning the account of his father, C. G. Calkins, of the Battle of Manila Bay in 1898.