Obolus galtensis

Billings, E. (1861-1865). Palaeozoic fossils. Volume I. Containing descriptions and figures of new or little known species of organic remains from Silurian rocks. 1: 1-426. Geological Survey of Canada (publication dates according to preface: 1-24 [Nov 1861], 25-56 [Jan 1862], 57-168 [Jun 1862], 169-344 [Feb 1865], 345-436 [Oct 1865]).

Rowell, A. J. (1963). Some Nomenclatural Problems in the Inarticulate Brachiopods. <em>Geological Magazine.</em> 100(1): 33-43.