NO. 1395. CAMBRIAN BRACHIOPODA—WALCOTT. 331 



striae between the concentric lines. The inner lamella of the shell are 

 marked by fine radiating- strite and the inner surface by more or less 

 numerous punctse, ver}^ much as in 0. {L.) piinctatus. For its size the 

 shell may be considered as relatively thin, 



A single specimen of a ventral valve that is doubtfully referred to 

 this species was collected 3 miles south of Antelope Springs, Utah, in 

 limestone forming- a spur of the House Range. 



Formation and locality. — Middle Cambrian limestones of Fish 

 Spring Range near north end; also a little south of the middle of the 

 range, Utah. 



The exact stratigraphic horizon of the limestones carrying this 

 species is unknown. It is well up in the Middle Cambrian or in the 

 Upper Cambrian. 



OBOLUS (LINGULELLA) QUADRILATERALIS, new species. 



General form rounded, quadrilateral; moderatelv convex. Surface 

 marked by concentric lines and ridges of growth, with line stria? 

 between. The surface of the inner layers of the shell is shiny and 

 marked by tine radiating strise in addition to the concentric lines. 

 The shell is rather thin; it is built up of several layers. 



This species differs from other described species by its subquadri- 

 lateral outline. In this respect it may be compared with (>. ( AYcstonki) 

 chuaTen^u., from which it differs in having a thinner shell and different 

 surface markings. 



Formation and locality. — Middle Cambrian. Coosa Valh\y shales., 

 Cedarbluff', Cherokee County, Alabama. 



OBOLUS (LINGULELLA) SEPTALIS, new species. 



The dorsal valve is all that is known of this little shell. There are 

 two specimens in the collections of the United States National Museum 

 and three in the collection of Mr. Bryan E. Walker, of Toronto, 

 Canada. 



The general form of the valves is much like that of (). (Z.) rotanda- 

 tus. It is distinguished from the latter and other described species by 

 the strong median ridge and septum of the dorsal valve. The outer 

 surface is marked by concentric striee and lines of growth and very 

 fine irregular concentric striae that give a minutely rough surface. 



Formation and locality. — Middle Cambrian. Silicious shales, Mount 

 Stephen, British Columl)ia. 



OBOLUS (LINGULELLA) UPIS, new species. 



This is a small, elongate shell of the group to which (>. (Z.) oras 

 belongs. It differs from the latter in being more elongate and in its 

 marked surface characters, and from 0. (Z.) collicia, O. {L.)Jliimensis.^ 

 (). (Z.) canius., and allied forms, in having a thick, strong shell and 

 highly characteristic exterior surface. 



