778 CAMBEIAN BRACHIOPODA. 



Upper Cambrian: (30w) Drift bowlder 6i limestone supposed to have come from la of the Notch Peak limestone 

 on Notch Peak [Waleott, 1908f, p. 175], found about 2 miles (3.2 km.) south of Marjum Pass, House Range [Walcott, 

 1908f, PL XIII], Millard County; (331) limestones in pass between the Pavant Mountains and the Canyon Range, a 

 few hundred yards east of the divide, on the road between Holden and Scipio, Millard County; and (54r) drift pieces 

 of limestone from the west slope of the Wasatch Range, east of the Lakeview ranch, about 5 miles (8 km.) north of 

 Brigham, Boxelder County; all in Utah. 



(54b) About 1,200 feet (365.8 m.) above the Middle Cambrian and 25 feet (7.6 m.) below the top of the Upper Cam- 

 brian in the upper part of the limestone forming 1 of the St. Charles formation [Walcott, 1908f, p. 191]; (54c) about 

 1,100 feet (335.3 m.) above the Middle Cambrian and 120 feet (36.6 m.) below the top of the Upper Cambrian, in the 

 central part of the limestone forming 1 of the St. Charles formation [Walcott, 1908f, p. 192]; and (54d) about 1,050 feet 

 (320 m.) above the Middle Cambrian and 175 feet (53.3 m.) below the top of the Upper Cambrian in the lower part 

 of the limestone forming 1 of the St. Charles formation [Walcott, 190Sf, p. 192]; all in Blacksmith Fork Canyon, about 

 10 miles (16.1 km.) east of Hyrum, Cache County, Utah. 



(158) Limestones north of East Gallatin River, near Hillsdale; and (3401j) limestone at the mouth of Fourmile 

 Creek; both in the Threeforks quadrangle (U. S. Geol. Survey), Gallatin County, Montana. 



(327) Arenaceous limestone east of Gold Camp, in the Caballos Mountains, New Mexico. 



(14k) Limestone on Wolf Creek, 15 miles (24.2 km.) west-southwest of Sheridan, Bighorn Mountains; and (168) 

 limestone on north side of Tepee Creek, beside the road from Sheridan to Dome Lake, Bighorn Mountains; both in 

 Sheridan County, Wyoming. 



(346b) Conococheague limestone, 2.75 miles (4.4 km.) south of Mercersburg, Franklin County, Pennsylvania. 



Specimens tliat are somewhat doubtfully referred to this species occur at the following 

 locaUties : 



Upper Cambrian.: (152) Limestone on ridge between Churn and Cottonwood Canyons, west side of Bridger Range; 

 and (154) limestone in hill on west side of Dry Creek, opposite mouth of Pass Creek, about 5 miles (8 km.) north of 

 Hillsdale, Threeforks quadrangle (U. S. Geol. Survey); both in Gallatin County, Montana. 



Upper? Cambrian: (306) Sandy limestone on Gravel River, eastern slope of the Rocky Mountains, in the 

 Mackenzie River basin, British Columbia. 



EOORTHIS DESMOPLEUEA NYMPHA (Walcott). 

 Plate XCVI, figure.2. 



Orthis (Plectorthis) desmopleura nympha Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 262. (Characterized as below 

 as a new variety.) 



This variety is based on strongly convex ventral valves in which the surface is marked by 

 fine radiating striae, separated into bands of 3 to 6 striae by stronger and more elevated strise. 

 Some shells show concentric lines and often ridges of growth that give an imbricated appear- 

 ance to the portion of the surface beyond the umbo. 



Formation and locality. — Lower Ordovician: (186) Near line of contact between red and gray Ordovician 

 limestone, in red siliceous limestone about 30 feet (9.1 m.) above the pre-Cambrian rocks, Williams Canyon, Manitou, 

 El Paso County, Colorado. 



Upper Cambrian: (168) Limestone on north side of Tepee Creeh, near the road from. Sheridan to Dome LaJce, Bighorn 

 Mountains, northern Wyoming. 



EOORTHIS ? DIABLO (Walcott) . 



Plate XCIII, figure 3. 



Orthis (Plectorthis) diablo Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 262. (Described as below as a new species.) 



This species is founded on a small, transverse shell that is marked by a few prominent 

 radiating costse that extend from the umbo to the margin of the shell. In the cast the costse 

 have a sharp summit and slope evenly to a narrow space between them. 



A ventral valve 9 mm. in height has a width of 14 mm., which is about the average propor- 

 tion of the specimens in the collection. The casts of the ventral valve show a rather low area 

 divided by a delthyrium, the inner angles of which have a rather strong tooth. The dental 

 plates extend backward farther than in most species of the genus, becoming attached to the 

 bottom of the valve only near the teeth, and not extending forward as in EoortJiis remnicha to 

 form a pseudospondylium. None of the specimens in the half dozen shells in the collection 



