CAMBRIAN BRACHIOPODA — WALCOTT 69 



OBOLUS (WESTONIA) NOTCHENSIS, new species 



Plate 7, Figure 13 



This species is represented by two specimens of the ventral valve 

 that have the general outline of Lingulclla ampla (Owen) [1852, 

 p. 583]. The exterior surface is marked by concentric lines of 

 growth and transverse, irregular, imbricating lines much like those 

 of O. {W.) stoncanus (Whitfield) [1882, p. 344] and O. {W.) iphis 

 Walcott [1905a, p. 336]. The form of the valve differs from that 

 of the latter species. 



The largest specimen has a length of 11 mm., \vith a maximum 

 width of 9 mm. 



Formation and Locality. — Lower Ordovician : Thin-bedded, 

 bluish-gray limestone ; at the summit of Notch Peak, House Range, 

 Millard County, Utah. 



OBOLUS (WESTONIA) WASATCHENSIS, new species 



Plate 8, Figures i and la 



This species is founded on some large shells that differ from 

 Oholus (JVestonia) ella (Hall and Whitfield) [1877, P- 232] in 

 attaining a larger size and greater proportional width and in having 

 the surface marked by radiating lines that extend from the umbo 

 with a gentle curvature toward the sides and front of the shell, so 

 as to terminate at right angles to the margin, very much as in O. 

 (IV.) finlandcnsis Walcott [1902, p. 611]. 



In the Blacksmith Fork section of the Middle Cambrian terrane, 

 in the Wasatch Mountains of northern Utah, O. {W.) wasatchensis 

 occurs 1,590 feet (484.6 m.) higher in the section than O. {W.) ella. 



Formation and Locality. — Middle Cambrian: (i) Shales about 

 950 feet (289.6 m.) above the Cambrian quartzitic beds, 2 miles 

 (3.22 km.) southeast of Muskrat Spring, on the northwest face of 

 Grantsville Peak, Stansbury Range, Tooele County; (2) about 1,700 

 feet (518.2 m.) above the Cambrian quartzitic beds; (3) about 

 2,300 feet (701 m.) above the Cambrian quartzitic beds; and (4) 

 a drift block supposed to have come from the horison of (2) ; all 

 three in W^asatch Canyon, east of Lakeview Ranch, 5 miles (8.05 

 km.) north of Brigham, Box Elder County; (5) about 1,500 feet 

 (457.2 m.) above the Cambrian quartzitic beds, one mile (1.61 km.) 

 northwest of Geneva (Copenhagen), east of Brigham, Box Elder 

 County; (6) about 3,150 feet (960.1 m.) above the top of the Cam- 



