538 CAMBRIAN BRACHIOPODA. 



Matthew's material is poor, but in the collections made by S. Ward Loper there is an 

 abundance of specimens showing some variations in form. The surface is marked by strong, 

 concentric lines of growth, with narrow bands of finer and somewhat minutely irregular striae. 

 Depressed, irregular, and bifurcating radiating hues show on very perfectly preserved shells. 



Formation and locality. — Middle Cambrian: (13i) Sandstones of the "Johannian" Division of Matthew's 

 section, on Gillis Brook, East Bay, east of Bras d'Or Lake; and (13r) sandstone at a little different horizon than that 

 of Locahty 13i, on Gillis Brook, East Bay, east of Bras d'Or Lake; and (ISn')" sandstones of Division E3e of Mat- 

 thew's [1903, p. 21] Eicheminian, Dugald Brook, Indian River; all in eastern Cape Breton, Nova Scotia. 



1 LiNGULELLA UPIS (Walcott) . 



Plate XXXVI, figures 3, 3a. 



Obolus (Lingulella) ripis Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, pp. 381-332. (Described and discussed as 

 below as a new species. ) 



This is a small, elongate shell of the group to which Lingulella ora (Walcott) belongs. It 

 differs from the latter in being more elongate and in its marked surface characters, and from 

 L. collicia (Matthew), L. fiumenis (Matthew), L. cania (Walcott), and allied forms, in having 

 a thick, strong shell and highly characteristic exterior surface. 



The shell is thick, the anterior jjortions being made up of numerous lamellae oblique to 

 the exterior surface, in this respect resembling some of the species of Obolus having thick 

 shells. The exterior surface is marked by concentric lines of growth, witli very fine, some- 

 what irregular striae between them. These show very distinctly in the anterior portion of 

 the shell. Further back they become very irregular, giving a crenulated appearance to the 

 striae and lines of growth, and the surface looks as though it was fornaed of thin, imbricating 

 scales or lamellae. 



Ohsen:ations. — The surface of Lingulella upis suggests that of Oiolus ( Westonia) euglyphus 

 (Walcott), but I have been unable to find traces of the transverse lines characteristic of Westonia. 



Formation and locality. — Upper Cambrian: (14g and 141) b Upper part of the limestones exposed 1 mile {1.6 km.) 

 west of Cherokee, San Saba County; and (14b) limestone on Cold Creek, at north end of gorge opposite the north end 

 of Sponge Mountain, 2 miles (3.2 km.) south of the San Saba County line, in Llano County; both in Texas. 



LlNGtJLELLA AVANNIECKI Redlich. 



I/' 



Plate XXXIX, figui-es 1, la-n. 



Lingulella ivanniecki Redlich, 1899, Mem. Geol. Survey India, Paleontologia Indica, new ser. , vol. 1, No. 1, The 

 Cambrian Fauna of the Eastern Salt Range, p. 7, PI. I, figs. 9a-d. (Described and discussed as a new species.) 



Obolus (Lingulella) wanniecki (Redlich), Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 332. (Described and dis- 

 cussed as below.) 



General form broadly ovate, with the ventral valve obtusely acuminate and the dorsal 

 valve rounded subtriangular; convexity moderate in the specimens embedded in argillaceous 

 shales. There is considerable range of variation in the outline of the valves; this is shown 

 in Plate XXXIX, for the ventral valve by figures 1, la-f, and for the dorsal valve by figures 

 Ig-m. All that is known to me of the interior markings of the ventral valve is shown b}^ 

 figures Id-f, and of the dorsal valve by figures ll-n. The surface of the shell is marked by 

 concentric lines of growth and very fine closely undulating raised striae that inosculate so as to 

 give the surface a granulated appearance. This type of surface occurs on Lingulella isse (Wal- 

 cott) and L. upis (Walcott). The anterior layers of the shell are marked by radiating and 

 concentric striae, and the interior of the shell has scattered punctae in addition to the radiating 

 and concentric strias. The shell is relatively thick and formed of several layers or lamellae 

 in addition to the very thin outer ornamented layer. 



The visceral area of the ventral valve is short, and the main vascular sinuses are about 

 halfway between the center of the shell and the lateral margins. In the dorsal valve the 



" ISn' is the type locality, but the specimens in the United States National Museum to which that number is assigned were collected later 

 than the type specimens. 

 & 14i is the type locality. 



