558 CAMBEIAN BRACHIOPODA. 



Ohservations. — This species is related by its form to LinguleUa (Lingulejns) gregwa (Mat- 

 thew) and L. (L.) longinervis (Matthew), but it differs in its surface characters. In its very- 

 fine, irregular strise and general form it is closely allied to L. {L.) exigua (Matthew). The 

 thick, robust shell and numerous strong pits on the inner surface of the shell give the latter 

 a character not seen in L. (L.) roberti. 



The visceral area and muscular scars of the ventral and dorsal valves are much like those 

 of Oholus selwyni (Matthew) (PL XXXVII), and in specimens of the same size occupy relatively 

 the same position. The specific variations between the two species appear to be in the shape 

 of the valves and the character of the finer ornamentation of the surface. 



Matthew originally [1895, p. 257] referred this species to the Ordovician fauna, but in 

 his review of the Cambrian fauna of Cape Breton [1903, p. 132] it is referred to his lower 

 Etcheminian. 



The specific name was given in honor of Mr. J. Alfred Robert, of the Geological Survey of 

 Canada, who collected the specimens of the species. 



Formation AND LOCALITY. — Middle Cambrian : (307d [Matthew, 1903, p. 132]) Sandy limestone of Division E2a? 

 of Matthew's Etcheminian, on Young (McFees) Point [Matthew, 1903, p. 19], near George River station, Cape Breton, 

 Nova Scotia. 



LiNGXJLELLA (LiNGULEPIS) EOWEI (Walcott). 



Plate XXI, figures 4, 4a-b. 



Oholus (Lingulepis) rowei Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 334. (Characterized as a new species.) 



This shell differs from LinguleUa (Lingulepis) acuminata (Conrad) and other species of 

 LinguleUa and LinguleUa (Lingulejns) in the sharp, fine, concentric ridges of the outer surface, 

 about six to the millimeter. This surface resembles closely that of Oholus (Palseoholus) ire- 

 tonensis Matthew. The material is not well preserved, but there is sufficient to illustrate the 

 form of the valves and the character of the surface. A fragment shows a more attenuate 

 posterior portion of a ventral valve than the one illustrated. 



The specific name is given in memory of Mr. R. B. Rowe, assistant geologist of the 

 United States Geological Survey, who collected the material a short time before his death. 



Formation and locality. — Lower Cambrian: (14p) Reddish-brown quartzitic sandstone, near Resting (Fresh- 

 water) Springs, which is in the southwest corner of T. 21 N., R. 8 E., on Amargosa River, in the southeastern part 

 of Inyo County, California. 



LiNGULELLA (LiNGULEPIS) SPATULA (Walcott). 



Plate XIX, figures 5, 5a-b. 



Obolus {LinguleUa) spatulus Walcott, 1902, Proc. U. S. Nat. Mus., vol. 25, p. 607. (Described and discussed as below 

 as a new species.) 



General form of the ventral valve spatulate, the sides sloping from the apex forward with 

 a very slight curvature to the anterior fifth of the sliell, where they pass into the broadly 

 rounded frontal margin. 



Dorsal valve ovate with the greatest width toward the front. Convexity moderate, and 

 about equal in both valves. A ventral valve 9 mm. in length has a convexity of about 1 mm. 

 A fragment of the outer surface indicates that the surface was relatively smooth, being broken 

 only by fine, scattered strise of growth. The inner layers show concentric lines, also fine, 

 radiating striae. The interior of the sheU was marked by scattered pustules, concentric striae, 

 and a few radiating lines. 



The largest ventral valve has a length of 9 mm. and a width of 6 mm. A dorsal valve 

 5 mm. in width has a length of 7 mm. 



The only trace of the vascular system preserved is the median ridge of the dorsal valve, 

 which extends forward to the anterior fourth of the shell. 



Observations. — This very pretty httle shell occurs in abundance in the chocolate brown 

 sandstone interbedded in the shales, just above the massive "Ton to" sandstone. It is distinct 



