OBOLID^. 423 



, i^ Obolus sp. undt. c. 



An exfoliated dorsal valve, probably belonging to the genus Ohohis, occurs at the following 

 locality. The specimen is too imperfect for identification. 



Formation and locality. — Ordovician: (214a) Limestone near the base of the Pogonip limestone in the White 

 Pine district, White Pine County, Nevada. 



^ Obolus sp. undt. d. 



In the conglomerate limestone near Highgate Falls, Vermont, I collected a single specimen 

 of the ventral valve of a species of Oholus not unlike the ventral valve of Oholus mxra (Hall 

 and Whitfield) (PL X) of the E.ocky Mountain region. 



Its surface is marked by numerous fine radiating striae and by distiact, concentric, lamellose 

 lines of growth. The fossils associated with it in the same fragment of limestone indicate the 

 Upper Cambrian horizon. 



Formation and locality. — TTpper Cambrian: (87') Conglomeratic limestone 1 mile (1.6 km.) south-southwest of 

 Highgate Falls, Franklin County, Vermont. 



Obolus sp. undt. e. 



1 



Plate XV, figui-e 8. 



Obolus sp. Kayser, 1876, Beitrage zur Geologie und Paleontologie der argentinischen Republik, vol. 2, Paleontol. Theil, 

 Abth. 1, pp. 9-10, PL I, fig. 14. (Described and discussed in German. Fig. 14 is copied in this monograph, 

 PL XV, fig. 8.) 



This form is illustrated by a single specimen of what appears to be the ventral valve. 

 Kayser [1876, p. 9] states that most of the specimens are mere fragments and only the genus 

 can be determined. He suggests that it may be Oholella, but from our present knowledge of 

 that genus it is not probable. The figure recalls forms of Obolus matinalis (Hall) and 0. anceps 

 Walcott. 



Formation and locality. — ^Upper Cambrian: (389b [Kayser, 1876, p. 9]) Sandstone at Tilcuya, Province of Jujuy, 

 Argentina, South America. 



Obolus 1 sp. undt. f. 



Plate XV, figure 9. 



Lingulella sp. Kayser, 1883, China, by Richthofen, vol. 4, p. 35, PL III, fig. 2. (Characterized and discussed in 

 German. Fig. 2 is copied in this monograph, PL XV, fig. 9.) 



Kayser [1883, p. 35] states that the remains of this species available for study are too 

 imperfect to permit accurate description and comparison. The shell preserves traces of radial 

 striation and strong concentric strise of growth. Attention is called to the fact that it has a 

 somewhat similar outline to Lingulella nathorsti Linnarsson (PL XXXI). 



The resemblance to the Oholus described by Kayser [1876, p. 9] from Tilcuya, Argentina, is 

 noticeable, and like that species it recalls Oholus matinalis (PL VIII). Comparison should also 

 be made with Dicellomus politus (Hall). 



Formation and locality. — Upper Cambrian: (332 [Kayser, 1883, p. 35]) Limestone at Saimaki, Province of 

 Liaotung, China. 



Obolus sp. undt. g. 



Obolus (?) sp. indet., Linnarsson, 1876, Bihang till K. svensk. Vet.-Akad. Handl., Bd. 3, No. 12, p. 16, PL III, 

 fig. 31. (Described and discussed in English. See below for copy of description.) 



The original description by Limiarsson follows : 



Because of its general shape, I refer to the genus Obolus a species of which the materials are very unsatisfactory, 

 so that I will not create for it a specific name, though it is easily distinguished from all the primordial Brachiopoda of 

 Sweden. The best specimen is an interior, somewhat mutilated anteriorly, and with the innermost shell layers partly 

 exfoliated . Its width is 16 mm . , the length about 14 mm . The shell is very slightly convex ; i ts circumference resembles 

 a sector of a circle; the front is broadly rounded; the slopes forming the beak seem to be nearly straight, and make a 



