792 



CAMBRIAN BRACHIOPODA. 



than the dorsal. The largest ventral valve in the material available for study has a length 

 of 9 mm. 



The specific name was given in honor of Dr. Carl Wiman. 



Formation and locality. — Passage beds between the Upper Cambrian and the Ordovician: (310j) Ceratopyge 

 limestone at Borgholm, Oeland Island, Sweden. 



(8x) Limestone at Slemmeatad, about 3 miles (4.8 km.) southwest of Christiania, Norway. 



Upper Cambrian: (390b [Moberg and Segerberg, 1906, p. 71]) Limestones of the Shumardia zone (zone 3) at Fogel- 

 sang, 5 miles (8 km.) east of Lund, Province of Malmohus; and (390c [Moberg and Segerberg, 1906, p. 70]) Ceratopyge 

 slate (Zone 3) at Wentlinge, on Oeland Island; both in Sweden. 



(323w) Black argillaceous shale of Division 3a^, at Christiania, Norway. . 



EooETHis ZENO Walcott. 



Text figures 71A-B'. 



Eoorthis zeno Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 3, p. 106, PI. 10, fig. 8. (Discussed as below as a 

 new species. Fig. 8 is copied in this monograph as fig. 71A.) 



In outline the ventral valve of this species is somewhat similar to that of some forms of 

 Eoorthis remnicTia winfiel/lensis (Walcott) (PI. XCI, fig. 2d), but it differs in having finer radiating 



ribs and in its smaller size. 

 It is also much smaller 

 than Eoorthis newherryi 

 Walcott, and it occurs 

 4,390 feet (1,338 m.) lower 

 in the same sti-atigraphic 

 section. The character of 

 the surface is shown by 

 text figure 7lB', and the 

 general form by text fig- 

 ure 71 A. I do not know 

 of any similar form, with 

 such regular, fine, sharp 

 radiating ribs, from the 



riGUKE 71.— Eoorthis zeno Walcott. A, A', Exfoliated ventral valve (U. S. Nat. Mus. Cat. No. 52397a). 



B, Fragment of dorsal valve (U. S. Nat. Mu.«i. Cat. No. 52397b). B', Enlargement of portion of 



surface of B (X 10). 



The specimens represented are from Locality 54o, Middle Cambrian Ute limestone in Blacksmith 

 Fork, about 10 miles (16.1 km.) east of Hyrum, Cache County, Utah. Figure 71A is copied from 

 Walcott [1908d, PI. X, fig. 8). It is the type specimen. 



Cambrian. The largest ventral valve in the collection has a length of 10 mm.; width, 18 mm. 



Formation and locality. — Middle Cambrian: (31c and 64o) « About 900 feet (274.3 m.), above the Brigham 

 quartzite and 3,300 feet (1,005.8 m.) below the Upper Cambrian in the limestone forming lb of the Ute limestone 

 [Walcott, 1908f, p. 196], in Blacksmith Fork Canyon, about 10 miles (16.1 km.) east of Hyrum, Cache County, Utah. 



Eoorthis sp. undt. a (Pompeckj). 



Orthis sp., Pompeckj, 1896, Jahrb. K.-k. geol. Reichsanstalt for 1895, Bd. 45, Hft. 3, p. 514, PI. XV, fig. 6. (Charac- 

 terized in German; see below for translation.) 



Orthis (Plectortkis) sp. (Pompeckj), Walcott (in part), 1905, Proc. U. S. Nat. Mus., vol. 28, pp. 272-273. (Original 

 description copied.) 



Tliis species appears, from the illustration given by Pompeckj [1896b, PI. XV, fig. 6], to 

 belong to the genus Eoorthis. The material is too imperfect for specific determination. The 

 original description is as follows: 



Some impressions of dorsal valves depart from Orthis romingeri. The ribs are remarkably broad, flat, and separated 

 by narrow interspaces; ribs may be observed to be split several times. 



Formation and locality. — Middle Cambrian: (345 [Pompeckj, 1896b, p. 514]) Greenish shale in the Paradoxddes 

 zone, on the Dlouhd, Hora, above the brook of Sbirov, near Skrej, Bohemia, Austria-Hungary. 



Eoorthis sp. undt. b (Pompeckj). 



(Char- 



Orthis sp. Pompeckj, 1896, Jahrb. K.-k. geol. Reichsanstalt for 1895, Bd. 45, Hft. 3, p. 514, PI. XV, fig. 7. 



acterized in German; see p. 793 for translation.) 

 Orthis (Plectorlhis) sp. (Pompeckj), Walcott (in part), 1905, Proc. U. S. Nat. Mus., vol. 28, pp. 272-273." (Original 



description copied.) 



54o is the type locality. 



