Summary[
edit] Description: English: Illustration of the jaw of the early tetrapod Occidens portlocki: inner surface (top) and outer surface (bottom). Modified from Plate XIII 13a and 13b of Report on the Geology of the County of Londonderry, and of Parts of Tyrone and Fermanagh by J. E. Portlock (Andrew Milliken, Grafton-Street; Hodges and Smith, College-Green; Longman, Brown, Green, and Longmans, London; 1843). The jaw was not recognized as belonging to a tetrapod until 2004; Portlock attributed it to the fish Holoptychius, illustrating it with scales and teeth of the fish. Date: 6 June 2014, 16:39:08. Source:
https://books.google.com/books?id=8lWrRans0oEC&pg=PA811#v=onepage&q&f=false. Author: J. E. Portlock.