Ferdinand ZirkelBorn 20 May 1838; died 12 Jun 1912 at age 74.German geologist and micropetrographist who was a pioneer in microscopic petrography, the study of rock minerals by viewing thin slices of rock under a microscope and noting their optical characteristics. He travelled in the U.S. through the Park Range mountains of the Continental Divide with the King Survey in 1871, and his name was given to the 12,180 foot tall peak as Mount Zirkel, in northwestern Colorado. The King Survey was one of the four “Great Surveys,”the federally sponsored expeditions to the West resumed after the Civil War. These differed from their pre-Civil War surveys in their greater inclusion of civilian specialists, particularly scientists. Zirkel wrote one of the 7 volumes of the King expedition Report, Vol. VI: Microscopial Petrography (1876).