676 CAMBRIAN BRACHIOPODA. 



limestones on the east side of West Gallatin {Gallatin) River, above Gallatin, Gallatin County; and (156a) limestones 

 of the Flathead formation of Peale, north of East Gallatin River, near Hillsdale, Gallatin County; all in Montana. 

 (4n) Limestone about 325 feet (99.1 m.) above the unconformable base of the Cambrian in divide at the head of 

 Jackson Creek (locally known as Sheep Creek), a creek flowing into Jackson Lake about 0.5 mile (0.8 km.) south of its 

 northwest corner, Teton Mountains, Grand Teton quadrangle (U. S. Geol. Survey), Uinta County; and (340d) lime- 

 stone near the head of Bear River Canyon; both in Wyoming. 



ACROTRETA ATTENUATA var. ? Walcott. 

 Plate LXV, figure 2. 



Acrotreta attenuata Meek (in part), 1873, Sixth Ann. Rept. U. S. Geol. and Geog. Survey Terr, for 1872, p. 463, footnote. 



(These specimens were included by Meek with the specimens which he listed as Acrotreta subconica and described 



in a footnote as A. attenuata. See also A. attenuata and A. idahoensis.) 

 Acrotreta attenuata Meek, var.?, Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 298. (Reason given for separation as 



variety.) 



A shell with a distinctly marked false area is separated as a variety of Acrotreta attenuata. 

 It is associated with the type specimen of A. attenuata. 



Formation and locality. — Middle Cambrian: (302) Limestone east of West Gallatin (Gallatin) River, above 

 Gallatin, Gallatin County, Montana. 



Acrotreta babel Barrande. 



"^ Plate LXXVII, figures 6, 6a-b. 



Acrotreta babel Baerande, 1879, Systfime silurien du centre de la Boheme, vol. 5, pt. 1, PI. XCV, figs, vii: 1-2. (Not 

 described, but figured as a new species. Figs. 2A, 2B, and 2C are reproduced in this monograph, PL LXXVII, 

 figs. 6, 6a-b, respectively.) 



This minute species is the only form of this genus that has been identified from Bohemia 

 by Barrande. It has the characters of the genus, and with the figures for comparison with 

 other species it appears to be distinct from all others. Barrande [1879b, PI. XCV, fig. vii: 1] 

 illustrates a more conical shell from Trubin than that represented by figures 6 and 6a, wliich 

 may belong to another species and genus. 



Formation and locality. — Lower Ordovician : (303) Etage dS, Konigshof; and (303a) Etage d3, Trubin; both 

 [Barrande, 1879b, PL XCV] in Bohemia, Austria-Hungary. 



Acrotreta baileyi Matthew. 



r /' ■ 



Plate LXXVII, figures 2, 2a-d. 



Acrotreta baileyi Matthew, 1886, Trans. Roy. Soc. Canada for 1885, 1st ser., vol. 3, sec. 4, No. 4, pp. 36-37, PL V, 



figs. 13, 13b-d. (Described and discussed as a new species. The specimens represented by figs. 13, 13c, and 



13d are redrawn in this monograph, PL LXXVII, figs. 2a, 2, and 2', respectively.) 

 Acrotreta baileyi Matthew, Hall and Clarke, 1892, Eleventh Ann. Rept. State Geologist New York for 1891, PL III, 



figs. 28-30. (Figs. 28 and 30 are drawn from the specimens figured by Matthew, 1886, PL V, figs. 13c and 13, 



respectively.) 

 Acrotreta baileyi Matthew, Hall and Clarke, 1892, Nat. Hist. New York, Paleontology, vol. 8, pt. 1, p. 102, PL III, 



figs. 32-34. (Discussed. Figs. 32-34 are copied from figs. 28, 30, and 29 of the preceding reference.) 

 Not Acrotreta baileyi? Matthew, 1892, Trans. Roy. Soc. Canada for 1891, 1st ser., vol. 9, sec. 4, No. 5, p. 43, PL XII, 



fig. 7d (referred to A. bisecta). 

 Acrotreta baileyi Matthew, 1902, Bull. Nat. Hist. Soc. New Brunswick, vol. 4, pt. 5, No. 20, p. 395, PL XVI, figs. 



la-d. (Mentioned and dimensions given. Figs, copied from Matthew, 1886, PL V, figs. 13, 13b-d.) 

 Acrotreta baileyi Matthew, Walcott, 1902, Proc. U. S. Nat. Mus., vol. 25, pp. 581-582. (Described and discussed 



as below.) 

 Acrotreta baileyi Matthew, 1903, Geol. Survey Canada, Rept. Cambrian Rocks Cape Bieton, p. 97, PL III, figs. la-d. 



(Mentioned. Figures are copied from Matthew, 1886, PL V, figs. 13, 13b-d.) 



General outliae transversely oval, with the posterior margin more or less straight for less 

 than one-half the transverse diameter of the shell. On the ventral valve the posterior margin 

 is rounded in at the median furrow of the false area, and on the dorsal valve it curves gently 

 from the cardinal slopes to the beak. 



The ventral valve is strongly convex with the apex about one-fourth the length of the 

 valve from the posterior margin. The crushed condition of the shells does not permit 



