Saturday, February 19, 2022

Prodromites (Goniatites) gorbyi Drawing

This image was scanned and Photoshop enhanced from Plate XV figure 1 in Indiana Department of Geology and Natural Resources Seventeenth Annual Report 1891 by  Sylvester Scott Gorby (1848-1930). It is described on page 700 as a new species Goniatites gorbyi (Miller, 1891). "Collected by R. A. Blair, in the lower part of the Choteau limestone or Waverly Group, at Pin Hook Bridge, in Pettis County, Missouri, and now in the collection of the author (Samuel Almond Miller [1836-1897]). The specific name is in honor of Prof. S. S. Gorby, State Geologist. The plate lists "FR BANK DEL" so that is who created the image.

This genus was renamed in 1901 in Prodromites, A New Ammonite Genus from the Lower Carboniferous by James Perrin Smith (1864-1931) and Stuart Weller (1870-1927) in The Journal of Geology April-May 1901 Volume 9, Number 3 pages 255-266. The write on page 259, "Neither the description nor the figure given by Miller of this type is accurate, the drawings of the septa being entirely too generalized." The specimen is now at the Paleontological Collection Walker Museum University of Chicago No. 6208. Diameter 114 mm, height of last whorl 64 mm, height of last whorl from the proceeding 35 mm. They put a picture on Plate VI, figure 1 shown below:

It does not appear the Walker Museum exists any more. The building is now used by the English department at the university.


Smith, James Perrin, and Stuart Weller. “Prodromites, a New Ammonite Genus from the Lower Carboniferous.” The Journal of Geology, vol. 9, no. 3, The University of Chicago Press, 1901, pp. 255–66,