226 CMIBRIAN BRACHIOPODA. 



154. Upper Cambrian: 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. G. S.), Gallatin County, Mont. (A. C. Peale, 1885). 



Billingsella plicatella. 

 Eoorthis desmopleura?. 

 Eoorthis remnicha. 



155. Upper Cambrian: Limestone north of East Gallatin River, near Hillsdale, Threeforks quadrangle (U. S. 

 G. S.), Gallatin County, Mont. (A. C. Peale, 1888). 



Billingsella coloradoensis. 



155a. Middle Cambrian: Limestone north of East Gallatin River, near Hillsdale, Threeforks qu"drangle (U. S. 

 G. S.), Gallatin County, Mont. (A. C. Peale, 1888). 

 *Micromitra pealei. 



156a. Middle Cambrian: Limestones of the Flathead formation [Peale, 1893, p. 20], north of East Gallatin 

 River, near Hillsdale, Gallatin County, Mont. (A. C. Peale. 1888). 

 Acrotreta attenuata. 



156b. Upper Cambrian: Limestone north of East Gallatin River, at the north end of the Gallatin Valley, 

 Threeforks quadrangle (U. S. G. S.), Gallatin County, Mont. (A. C. Peale, 1884). 

 Billingsella plicatella. 



157 (same locality as 158 and 156, but different horizon). Upper Cambrian: Limestone north of East Gallatin 



River, near Hillsdale, Threeforks quadrangle (U. S. G. S.), Gallatin County, Mont. (A. C. Peale, 1888). 

 Billingsella plicatella. 

 Huenella abnormis. 



158 (same locality as 156, 157, and 158a, but different horizon). Upper Cambrian: Limestone north of East 



Gallatin River, near Hillsdale, Threeforks quadrangle (U. S. G. S.), Gallatin County, Mont. (A. C. 



Peale, 1889). 

 Dicellomus pectenoides. I Eoorthis desmopleura. 



*Billingsella plicatella. 1 Huenella abnormis. 



158a (same locality as 156. 157, and 158, but different horizon). Upper Cambrian: Limestone north of East 

 Gallatin River, near Hillsdale, Threeforks quadrangle (U. S. G. S.), Gallatin County, Mont. (A. C. 

 Peale, 1889). 

 Dicellomus nanus. 



159. Middle Cambrian: Limestones north of West Gallatin (Gallatin) River, Gallatin County, Mont. (A. C. 

 Peale, 1884). 



Micromitra pealei. 

 Obolus rotundatus. 

 Acrotreta attenuata. 



Billingsella coloradoensis. 

 Olenoides?. 



160. Upper Cambrian: Sandstones forming a remnant of the Gallatin formation which lies between the exposures 

 of "porphyrite" on the east side of Willow Creek [Peale, 1896, areal geology sheet], 12 miles (19.2 km.) 

 south-southwest of Threeforks, Threeforks quadrangle (U. S. G. S.), Gallatin County, Mont. (A. 0. 

 Peale, 1889). 



Micromitra (Paterina) superba?. 



160a. Upper Cambrian: Sandstone west of Bear Creek, south of the Gallatin Valley southwest of Bozeman, 

 Threeforks quadrangle (U. S. G. S.), Gallatin County, Mont. (A. C. Peale, 1889). 

 Obolus rotundatus. 



161. Upper Cambrian: Limestone on the south side of West Gallatin (Gallatin) River, northwest of Hamilton 

 on the north side of the Gallatin Valley, Gallatin County, Mont. (A. C. Peale, 1884). 



Obolus tetonensis. 

 Lingul'ella desiderata. 



163 (=55c). (For stratigraphic position and association, see p. 152.) (R. S. Spence.^ 

 Micromitra (Iphidella) pannula. 

 Acrothele subsidua. 

 *Acrotreta definita. 



164. Middle Cambrian: Sandstone in the Deadwood formation in the cliffs on the east side of the valley near 

 Deadwood, Black Hills, South Dakota. 

 Dicellomus pectenoides. 



164f. (For stratigraphic position and association, see p. 147.) Middle Cambrian: Shales just above a bed of 

 limestone on the road leading northwest out of Montevallo, Shelby County, Ala. 

 Obolus? sp. 



*Nisusia (Jamesella) nautes. 

 *Nisusia (Jamesella) spencei. 



