BILLINGSELLIDiE. 787 



Some of the shells referred to E. remnicha (PI. XCI, figs. 1,1a, and le) suggest Platystrophia 

 in their form and radiating ribs. 



Formation and locality. — TTpper Cambrian : (80a) "St. Croix sandstone," 4 miles (6.4 km.) north of Reedsbm-g, 

 Sauk County; (328q) "St. Croix sandstone" in quarry at Ableman, Sauk County; and (97a) "St. Croix sandstone," 

 near Winfield, Jefferson County; all in Wisconsin. 



(86a) "St. Croix sandstone," near Red Wing, Goodhue County, Minnesotafi 



(153a and 154) Limestone on west side of Dry Creek, near the mouth of Pass Creek, about .5 miles (8 km. ) north of 

 Hillsdale, Threeforks quadrangle (U. S. Geol. Survey), Gallatin County; (302n) limestone on the south side of the 

 Gallatin Valley, Gallatin County; and (4r) just above the Middle Cambrian in the limestones of the Gallatin formation of 

 Peale [1893, PL IV], on ridge 8 miles (12.8 km.) east of Yellowstone River, and 3 miles (4.8 km.) north-northeast of 

 Mount Delano, Livingston quadrangle (U. S. Geol. Survey), Park County; both in Montana. 



(168) Limestone on north side of Tepee Creek, beside the road from Sheridan to Dome Lake, Bighorn Mountains, 

 Sheridan County, Wyoming. 



(12k) Limestones of the Reagan sandstone (in the section 7 miles (11.2 km.) north of Springer this horizon is 

 about 225 feet (69 m.) above the porphyry contact and 55 feet (17 m.) below the Arbuckle limestone) on the west side 

 of Honey Creek, near the southeast corner of sec. 35, T. 1 S., R. 1 E., Ardmore quadrangle (U. S. Geol. Survey), 

 Carter County; (12n) limestones of the Reagan sandstone (in the section 7 miles (11.2 km.) north of Springer this 

 horizon is about 240 feet (73 m.) above the porphyry contact and 40 feet (12 m.) below the Arbuckle limestone), 

 NW, isec. 1, T. 2 S., R. 1 E., Ardmore quadrangle (U. S. Geol. Survey), Carter County; and (12p) about 225 feet (69 m.) 

 above the igneous rocks in the limestones of the Reagan sandstone, at the northwest extremity of the Arbuckle Moun- 

 tains, about 4 miles (6.4 km.) east of Homer, Carter County; all in Oklahoma. 



Middle Cambrian: (302b) Limestone near Crowfoot Ridge, Gallatin quadrangle (U. S. Geol. Survey), Yellowstone 

 National Park, Wyoming. 



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

 locality : 



Middle Cambrian: (3x) About 2,200 feet (670.6 m.) above the Lower Cambrian and 2,200 feet (670.6 m.) below the 

 Upper Cambrian in the limestone forming Id of the Marjum limestone [Walcott, 1908f, p. 180], 2.5 miles (4 km.) east 

 of Antelope Springs, in ridge east of Wheeler Amphitheater [Walcott, 1908f, Pis. XIII and XV], House Range, 

 Millard County, Utah. 



EOORTHIS REMNICHA SULCATA (Walcott). 



\y 



Plate XCII, figures 1, la-c. 



Orthis (Plectorthis) remnicha sulcata Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 269. (Characterized somewhat 

 as below as a new variety.) 



Tliis variet}^ is founded on the strongly sulcate dorsal valve. The ventral valve shows 

 only a slight flattening of the median portion. Finlcelnburgia osceola (PI. XCIII) has a mesial 

 fold on the dorsal valve, but it is not so sharp. 



Formation and locality. — TTpper Cambrian : (80a) "St. Croix sandstone," 4 miles (6.4 km..) north of Reedshurg, 

 Sauh County; and (97a) "St. Croix sandstone" near Winfield, Jefferson County; both in Wisconsin. 



(339d) "St. Croix sandstone " at Taylors Falls, Chisago County ; and (97x) "St. Croix sandstone " at Reads Landing, 

 foot of Lake Pepin, Wabasha County; both in Minnesota. 



EOORTHIS REMNICHA TEXANA (Walcott). 

 Plate XCII, figures 4, 4a-g. 



Orthis (Plectorthis) remnicha texana Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 270. (Characterized as below as 

 a new variety.) 



The rounded, subquadrate form and the arrangement of the radiating costse serve to 

 differentiate this variety. The costae vary considerably on different shells, but the tendency 

 of the larger number is toward the surface represented by Plate XCII, figures 4c-g. Fine 

 radiating striae, similar to those represented by Plate XCII, figure 2c, of Eoorihis remnicha 

 occur on the ribs and interspaces. 



Formation and locality. — Upper Cambrian : (12m) Arbuckle limestone (in the section 7 miles (11.2 km.) north 

 of Springer this horizon is about 30 feet (9.1m.) above the Reagan sandstone), NE. \ sec. 2, T. 2 S., R. 1 E.; and (12n) 

 limestones of the Reagan sandstone (in the section 7 miles (11.2 km.) north of Springer this horizon is about 240 feet 



oN.n. Winchell [1S86, p. 317] gives the type locality as "St. Croix sandstone" in sewer excavation at the corner of Brush and Main 

 streets, Red Wing, Minnesota. 



