510 



CAMBRIAN BRACHIOPODA. 



Observations. — The ventral valves of Lingulella isse have an outline very similar to that 

 of Lingulella pogoJiipensis (Walcott) and L. acutangula (Roemer) (PL XVII), but the dorsal 

 valves are more subquadrate in outline, and even the elongate form of the dorsal valve is more 

 obtusely rounded. The species has a considerable vertical distribution in the House Range 

 section. It is first met with 9.50 feet (289.6 m.) above the Middle Cambrian, and again at 

 the 1,150 (350.5 m.) and 1,400 foot (426.7 m.) horizons. Fragments of a closely allied species 

 occur near the summit of the Upper Cambrian, 2,800 feet (853.4 m.) above the Middle Cambrian, 

 and a single dorsal valve was collected from the Weeks limestone of the Middle Cambrian, 

 650 feet (198 m.) below the base of the Upper Cambrian. If these two somewhat doubtful, 

 but still closely allied, shells are identical the known vertical range of the species is 3,450 feet 

 (1,052 m.), a range that may be compared with that of Obolus mcconnelli (p. 397) and L. desid- 

 erata (p. 493). 



The original description of the species [Walcott, 1905a, p. 330] referred it to theMiddle 

 Cambrian, but later collections from the House Range section shoAV this reference to have 



been incorrect, as the associated 

 fauna occurs in the Orr formation 

 30 miles to the south. 



Formation and locality. — Upper Cam- 

 brian: (15d)'' Thin-bedded blue limestone near 

 Cave Spring on the east side of the Fish Spring 

 Range, about 4 miles {6.4 km.) south of the 

 J. J. Thomas ranch; and (33d) thin-bedded 

 blue limestone from the same horizon as 

 locality No. 15d at the base of the first high 

 point southwest of the J. J. Thomas ranch, 

 on the east side of the Fish Spring Range; 

 both in Juab County, Utah. 



(30j) 950 feet (289.6 m.) above the Mid- 

 dle Cambrian and 2,450 feet (74G.8 m.) below 

 the top of the Upper Cambrian, near the base 

 of the arenaceous shales and limestone form- 

 ing le of the Orr formation [Walcott, 1908f, 

 ■p. 176], on Orr Ridge, about 5 miles (8 km.) 

 south of Marjum Pass; (30k) 1, 150 feet (350.5 

 m.) above the Middle Cambrian and 2,175 

 feet (662.9 m.) below the top of the Upper 

 Cambrian, at the top of the arenaceous shales 

 and limestones forming le of the Orr forma- 

 tion [Walcott, 1908f, p. 176], on Orr Ridge, 

 about 5 miles (8 km.) south of Marjum Pass; 

 (30y) about 1,400 feet (426.7 m.) above the Middle Cambrian and 1,900 feet (579.1 m.) below the top of the Upper 

 Cambrian in the supposed metamorphosed equivalent of the shales forming lb of the Orr formation [Walcott, 1908f, 

 p. 176], above the granite contact on top of the ridge north of Notch Peak; (31ct) about 2,800 feet (853.4 m.) above the 

 Middle Cambrian and 500 feet (152.4 m.) below the top of the Upper Cambrian in the gray limestone forming la of 

 the Notch Peak limestone [Walcott, 1908f, p. 175], on the north slope of Notch Peak; all in the House Range [Walcott, 

 1908f, Pis. XIII and XIV], Millard County, Utah. 



(34r and 34t) Limestone 1.5 miles (2.4 km.) northwest of Wahwah Springs, on the north side of the road at Cane 

 Pass, Wahwah Mountains, Beaver County; (32g) about 2,575 feet (784.9 m.) above the Cambrian quartzitic sand- 

 stones in a blue limestone about 2 miles (3.2 km.) southeast of Muskrat Spring, on the northwest face of Grantsville 

 Peak, Stansbury Range, Tooele County; and (30s) green shale about 1,200 feet (365.8 m.) above the Cambrian quartz- 

 itic sandstones on the pipe line above the limekiln in Ogden Canyon 1 mile (1.6 km.) above its mouth, east of Ogden, 

 Weber County; all in Utah. 



(313) Limestone 0.75 mile (1.2 km.) east-northeast of McGill post office, White Pine County, Nevada. 

 (57d) About 3,215 feet (980 m.) above the Middle Cambrian and 375 feet (114.3 m.) below the top of the Upper 

 Cambrian in green shales near the summit of 2b of the Sherbrooke limestone [Walcott, 190Sf, p. 204], on ridge west 

 of Mount Bosworth, on the Continental Divide between Alberta and British Columbia, just north of the Canadian 

 Pacific Railway, Canada. 



FiGUEE iZ.—Linouldla isse (Walcott). A, Ventral valve flattened and distorted in the 



shale (U. S. Nat. Mus. Cat. No. 51809a). B, Dorsal valve flattened in the shale (U. S. 



Nat. Mus. Cat. No. 51809b). C, C, Ventral valve (U. S. Nat. Mus. Cat. No. 5e998a). 



D, D', Dorsal valve (U. S. Nat. Mus. Cat. No. 56998b). E, Dorsal valve (U. S. Nat. 



Mus. Cat. No. 5099SC). F, Young shell tentatively referred to this species (U. S. Nat. 



Mus. Cat. No. 5699Sd). 



The specimens represented by figures 43A and 43B are from Locality 30k; those rep- 

 resented by figures 430, 43D, 43E, and 43F are from Locality 30j ; both in the Upper 

 Cambrian limestones of the Orr formation, House Range, Millard County, Utah. 



t The species also occurs in Locality 341 (p. 196). 



