NO. 3 CAMBRIAN AND OZARKIAN TRILOBITES 127 



Formation and locality. — Ozarkian: (552) St. Charles formation. 

 Blacksmith Fork Canyon, 10 miles (16 km.) east of Hyrum, Cache 

 County, Utah. 



XENOSTEGIUM GONIOCERCUM (Meek) 



Plate 24, figs. 5-8 



Asaphics (Mcgalaspis) gomocercus Meek, 1873, 6th Ann. Rept. U. S. Geol. 

 Surv., Terr., p. 480. 



Observations. — Several additional specimens and the original types 

 are figured for the first time, no previous illustrations of this species 

 having even been published. This species, of which only the pygidium 

 is known, differs from Xenostcginm hclcmniirmn with which it was 

 regarded as synonymous for several years, mainly in the character of 

 the axial and dorsal furrows delimiting the pygidial axis. The two 

 sides of the dorsal furrow in X. goniocerciim do not turn outward 

 before ceasing in X. belenmurum, and the axis is carried further 

 backward by a carinate ridge. 



Formation and locality.— CansLdinn ? near Malad, Idaho. The exact 

 locality is unknown. 



XENOSTEGIUM KIRKI, new species 



Plate 24, figs. 18-21 



Observations. — This species is closely allied to Xenostegiiim gonio- 

 cercum. The glabella is expanded to a slightly greater degree and its 

 better preservation permits a more complete illustration of the charac- 

 ters of the genus. The pygidium is also quite similar. 



Specific name given in recognition of the work of Dr. Edwin Kirk 

 of the U. S. Geological Survey in the Beaverfoot-Brisco-Stanford 

 Range area during the field season of 1923. 



Formation and locality. — Ozarkian: (17a) Mons formation. .5 

 mile (.8 km.) north of Stoddart Creek, 5.5 miles (8.8 km.) south 

 of Sinclair Canyon, British Columbia. 



(67q) Douglas Lake Canyon Valley, Sawback Range, Alberta, 

 Canada. 



XENOSTEGIUM SCHOFIELDI, new species 



Plate 24, fig. 15 



Observations. — This species difi^ers from Xcnostegium kirki in the 

 greater distance from the margin, where the axis terminates, and its 

 longer triangular outline. Otherwise it is quite similar. 



