800 



CAMBRIAN BRACHIOPODA. 



on the railroad track below the Cliff House, Devils Lake, Sauk County; (83) near Trempealeau, Trempealeau County; 

 (78) quarry near St. Croix River in the suburbs of Osceola, Polk County; and (134a) in a quarry 1 mile (1.6 km.) south- 

 east of the county courthouse in Menomonie, Dunn County; all in Wisconsin. 



Stntrophia calcifera (Billings) 

 Plate CIV, figm-es 1, la-i. 



Camerella calcifera Billings, 1861, Canadian Naturalist, vol. 6, pp. 318-320, figs. 3a-c, p. 319. (Described and discussed 



as a new species. Figs. 3a-c are copied in this monograph, PI. CIV, figs. 1, la, and lb,. respectively.) 

 Camarella calcifera Billings, 1863, Geol. Survey Canada, Fifteenth Bept. Progress, figs. 247a-c, p. 231. (No text 



reference. Figs. 247a-c are copied from figs. 3a-c of the preceding reference.) 

 Camerella calcifera Billings, 1865, Geol. Survey Canada, Paleozoic Fossils, vol. 1, p. 220. (Localities mentioned.) 

 Triplecia? calcifera (Billings), Hall and Claeke, 1892, Nat. Hist., New York, Paleontology, vol. 8, pt. 1, p. 270. (Merely 



changes generic reference.) 

 Syntrophia? calcifera (Billings), Hall and Clarke, 1893, idem, pt. 2, p. 218, PI. LXII, fig. 24. (Changes generic 



reference.) 



Syntrophia calcifera differs from S. nundina in its more pointed and incurved apex, stronger 

 ventral sinus, and dorsal fold. It is more convex and rotund than S. primordialis. 



The only interior parts known are in the form of a cast illustrated by Billings [1861a, fig. 3c, 

 p. 319] and copied in Plate CIV, figure lb; this indicates a well-developed spondylium and 

 a mecUan supporting septum in the ventral valve. 



The form owes its specific name to its occurrence in the "calciferous sandrock." 



Formation and locality. — Lower Ordovician: (319t)a "Calciferous sandrock" at St. Timothy on the St. Law- 

 rence, near the head of the Beauharnois Canal; (319u [Billings, 1861a, p. 320]) "calciferous sandrock" in the Township 



of Edwardstown, between Beauharnois and Lake 

 Champlain; (392) o at Nortons Creek; (392j)« litne- 

 stones of the ' ' Quebec group ' ' at Point Levis; and 

 (3931) o limestone at Phillipsburgh; all in the 

 Province of Quebec, Canada. 



(314c) a Nodules of white limestone belonging 

 to Division P of Billings's section at Cow Head, 

 Newfoundland. 



Syntrophia Cambria Walcott. 



Text figures 72A-D. 



Syntrophia cambria Walcott, 1908, Smithsonian. 

 Misc. Coll., vol. 53, No. 3, pp. 106-107, 

 PI. X, figs. 11 and 11a. (Described and 

 discussed as a new species. With the ex- 

 ception of the third paragraph the reference 

 is copied below. Figs. 11 and 11a are copied 

 in this monograph as figs. 72B and 72C, re- 

 spectively.) 



C D 



FiGimE 72.— Syntrophia cambria Walcott. A, A', Top view and side outline of 

 ventral valve (U. S. Nat. Mus. Cat. No. 57029a). B, Ventral valve, the type 

 specimen (U. S. Nat. Mus. Cat. No. 52477a). C, Dorsal valve (U. S. Nat. 

 Mus. Cat. No. 5247S). D, Partly exfoliated ventral valve (U. S. Nat. Mus. 

 Cat. No. 52477c). 



Figures 72B and 72C are copied from Walcott tl908d, PI. X, figs. U and 11a]. 

 The specimen represented by figure 72C is from Locality 34m ; those represented 

 by figures 72A, 72B, and 72D are from Locality 32e ; and that represented by figru-e 

 72A is from Locality 31c, all in the Middle Cambrian of northeastern Utah. 



General form transversely oval, 

 strongly convex but not rotund. Ven- 

 tral valve moderately convex, with the 

 frontal margin in adult shells prolonged ; 

 a flattened median sinus begins on the 

 umbo and widens to two-tliirds the 

 width of the shell in front; area un- 

 known. Dorsal valve moderately convex except on the median fold, which is rounded but 

 not unusually prominent; area unknown. 



Surface marked by a few concentric lines of growth. The largest dorsal valve has a length 

 of 8 mm.; width, 11 mm. A ventral valve 9 mm. in length has a width of 14 mm. 



a Billings, lS65a, p. 220. 



