His numerous papers and essays include Geologische Skizze van der Westkiisle Schottlands (1871); Die Struktur der Variolite (1875); Microscopical Petrography (in Report of U.S. Geol. Exploration of 4Oth Par., vol. vi., 1876); Limurit aus der Vallee de Lesponne (1879); Über den Zirkon (1880). His separate works include Lehrbuch der Petrographie (1866; 2nd ed. 1893, 1894); Die mikroskopische Beschaffenheit der Mineralien und Gesteine (1873).
This explanation is given by Professor FerdinandZirkel of Leipzig, Germany (one of the greatest Geologist and Petrologist) in a letter to Prof.
1603 Konrad Zirgle in Bavaria, a 'Kellermeister' of Duke Ferdinand, i.e.
The description of the Coat of Arms of the Zirkel Family was provided by courtesy of Herr Wilhelm Zirkel of Ravensburg, Germany, in a letter to Gordon Zirkle in Virginia, USA, and was translated by Mrs.