NO. 3 CAMBRIAN TRILOBITES 203 



Geographic distribution. — Appalachian Province: Virginia to 

 Alabama. 



Mississippian Province : Wisconsin, Texas. 



Cordilleran Province: Montana, northern Wyoming, Utah. 



China: Southwestern Manchuria, Shantung. Australia: Gipps- 

 land, Victoria. Identified from a pygidium.^ 



Observations. — This is a very valuable genus to the stratigraphic 

 geologist, owing to the wide distribution of several of the species, 

 notably C. texanus, C. thoosa, and C. tripunctatus. With more thor- 

 ough and systematic collecting, it will undoubtedly furnish very 

 important data for the subdivision of the various formations in 

 which the species and varieties occur. The persistence of a con- 

 siderable range of variation among the cranidia of C. texanus at the 

 several localities where the species occurs serves to strengthen the 

 identification of that species in Texas, Arizona, Wyoming, and 

 Alabama. 



The genus falls into the family Ceratopygid?e.^ The relatively 

 large pygidium with its postero-lateral spines is characteristic of 

 other genera referred to the family. 



The species now referred to Crepicephalus are: 



Crepicephalus augusta Walcott (pi. 29, figs. 6, 6a-h). 



Crepicephalus camiro Walcott (pi. 32, figs. 2, 2a). 



Crepicephalus comus Walcott (pi. 31, figs. 3, 3a). 



Crepicephalus convexus Walcott [The Cambrian Faunas of China, Walcott, 



Carnegie Institution of Washington, Vol. 3, Pub. No. 54, 1913, p. 140, 



pi. 13, figs. 16, i6a-b]. 

 Crepicephalus coosensis Walcott (pi. 32, figs. 3, 2a-f). 

 Crepicephalus coria Walcott (pi. 2>Z, figs. 3- 2>a-9)- 

 Crepicephalus dis Walcott (pi. 32, figs, i, la-c). 

 Crepicephalus daniia Walcott [The Cambrian Faunas of China, supra, p. 



141, pi. 13, figs. 14, 140-&]. 

 Crepicephalus etheridgei Chapman [Proc. Royal Soc. Victoria, n. s., Vol. 23, 



p. 319, pi. 58, fig. 8. Locality, Dolodrook River, N. E. Gippsland, 



Victoria]. 

 Crepicephalus iowcnsis (Owen) (pi. 29, figs, i, 2, 2a-/). 

 Crepicephalus liliana Walcott (pi. 29, figs. 5, 5a-c). 

 Crepicephalus texanus (Shumard) (pi. 29, fig. 7; pi. 30, figs. 1-4, 4a). 

 Crepicephalus texanus danace Walcott (pi. 29, figs. 3, ^a). 

 Crepicephalus texanus elongatus Walcott (pi. 29, figs. 4, 4a). 

 Crepicephalus thoosa Walcott (pi. 31, figs, i, la-k). 

 Crepicephalus tripunctatus (Whitfield) (pi. 33, figs, i, la). 

 Crepicephalus tripunctatus magnispinus Walcott (pi. 33, figs. 2, 2a-c). 

 Crepicephalus tumidus Walcott (pi. 31, fig. 2). 



^ Crepicephalus etheridgei Chapman. 



"Text-book of Palaeontology, Zittel-Eastman, 1913, Vol. i, p. 717. 



