174 CAMBRIAN BRACHIOPODA. 



9m. Middle Cambrian: Shale 4 miles (6.4 km.) above Walker's ranch, on North Fork of Dearborn River, in the 

 eastern part of the Lewis and Clark National Forest, Lewis and Clark County Mont. (C. D. Walcott, 

 1900). 

 Obelus (Westonia) ella. 



9ii (=326e). Lower Cambrian: Dark pm-plish siliceous shales on Pearl Street, North Weymouth, Norfolk County, 

 Mass. (H. T. Burr, 1900). 

 Obolella atlantica. 

 Callavia burri Walcott. 

 Callavia crosbyi Walcott. 



So. Middle Cambrian: Siliceous limestone about 15 feet (4.6 m.) above the Coronado quartzite [Lindgren, 1905, 

 p. 3], 0.5 mile (0.8 km.) southwest of Milk ranch, on the first spur north of the one which the main road 

 follows, Clifton quadrangle (U. S. G. S.), Graham County, Ariz. (J. M. Boutwell, 1901). 

 Lingulella lineolata. 

 Lingulella perattenuata. 



9p (about 115 feet above 9r; 55 feet above 12s; almost same horizon as 9x; 10 feet below 9t). (For stratigraphic 

 position and association, see p. 142.) Upper Cambrian: About 160 feet (48.8 m.) above the porphyry con- 

 tact in the limestone of the Reagan sandstone, in SE. J NE. J sec. 2, T. 4 N., R. 13 W., about 15 miles. 

 (24.2 km.) northwest of Fort Sill, Comanche County, Okla. (E. 0. Ulrich, 1901). 



Obolus tetonensis ninus. 

 *Lingulella ora. 

 Linnarssonella girtyi. 



Ptychoparia sp. 

 Chariocephalus sp. 

 Uleenurus sp. 



9q (50 feet below 12d). (For stratigraphic position and association, see p. 142.) Upper Cambrian: About 10 feet 

 (3 m.) above the porphyry contact and 90 feet (27.4 m.) below the Arbuckle limestone, in limestone of the 

 Reagan sandstone, in middle of west half of sec. 2, T. 4 N., R. 13 W., about 15 miles (24.2 km.) northwest 

 of Fort Sill, Comanche County, Okla. (E. 0. Ulrich, 1901). 



Obolus tetonensis ninus. 

 Lingulella ora. 



Lingulella (Lingulepis) acuminata. 

 Linnarssonella girtyi. 

 Linnarssonella girtyi?. 



Eoorthis wichitaensis- 

 Agnostus sp. 

 Agraulos sp. 

 Ptychoparia sp. 

 Pterocephalus sp. 



9r (about 125 feet below 9t; about 115 feet below 9p; see 9v). (For stratigraphic position and association, see 

 p. 142.) Upper Cambrian: About 45 feet (14 m.) above the porphyry contact in the limestone of the 

 Reagan sandstone, in SE. i NE. f sec. 2, T. 4 N., R. 13 W., 15 miles (24.2 km.) northwest of Fort Sill, 

 Comanche County, Okla. (E. O. Ulrich, 1901). 



Acrotreta microscopica. 



Agnostus sp. 



Ptychoparia sp. 



*Obolus tetonensis ninus. 

 Lingulella similis. 

 Linnarssonella girtyi. 



9s (believed to just overlie 9u). (For stratigraphic position and association, see p. 142.) Upper Cambrian: About 

 85 feet (26 m.) below the Arbuckle limestone, in the limestone of the Reagan sandstone, near middle of 

 west half of sec. 13, T. 4 N., R. 13 W., 13 miles (20.8 km.) northwest of Fort Sill, Comanche County, Okla. 

 (E. 0. Ulrich, 1901). 



Obolus tetonensis ninus. 1 Lingulella (Lingulepis) acuminata. 



Lingulella similis. | Eoorthis wichitaensis. 



9t (125 feet above 9r; 10 feet above 9p; 25 feet below 9u; see 9v). (For stratigraphic position and association, 

 see p. 142.) Upper Cambrian: About 170 feet (52 m.) above the porphyry contact in the limestone of the 

 Reagan sandstone, SE. J NE. i sec. 2, T. 4 N., R. 13 W., 15 miles (24.2 km.) northwest of Fort Sill, 

 Comanche County, Okla. (E. 0. LTlrich, 1901). 



Acrotreta microscopica. 



Eoorthis indianola. 



Ptychoparia sp. 



Obolus matinalis. 

 Obolus tetonensis ninus, 

 Lingulella similis. 



9u (believed to just underlie 9s; 25 feet above 9t). (For stratigraphic position and association, see p. 142.) Upper 

 Cambrian: About 195 feet (59.4 m.) above the porphyry contact in the limestone of the Reagan sandstone, 

 in SE. i NE. } sec. 2, T. 4 N., R. 13 W., 15 miles (24.2 km.) northwest of Fort Sill, Comanche County, 

 Okla. (E. O. Ulrich, 1901). 



Obolus tetonensis ninus. 

 Lingulella similis. 

 Eoorthis indianola. 

 Eoorthis wichitaensis. 



Syntrophia primordialis. 

 Agnostus sp. 

 Ptychoparia sp. 



