404 L'UUCEEDISGS OF TUE XJTIUXAL Mi\SEi2I. vol. xxi. 



OBOLUS (LINGULELLA) FRAGILIS, new species. 



General form ovate, with the ventral valve subacuminate and the 

 dorsal valve broad ovate; valves apparently moderately convex, as 

 determined from the specimens more or less compressed in the shale. 

 Surface of shell marked by concentric lines of growth and what 

 appears to be an exceedingly line papillose surface, which is ai)[)arently 

 produced by the inoscuhiting of irregular raised stria*, as on the sur- 

 face of (>. {L.) radiUm. When the outer layer of the shell is exfoliated 

 very tine concentric and radiating striae occur on the surface of the 

 inner layer. The shell is thin and formed of an outer layer and one or 

 more thin inner layers or lamella'. 



The average length of the ventral valve is about '> mm ; width, 4 mm. 

 Tlie dorsal valve is a little shorter. 



The rather long area of the ventral valve is divided midway by a 

 strong pedicle groove. The area of the dorsal valve is clearly defined 

 on casts of the interior. It is about three-fifths the width of the valve 

 and arched forward at the center. 



The casts of tlie interior of the valves show traces of the vascular 

 markings, but nothing very definite can be said of them. 



Ohservafiont;. — This pretty little species is closely related to ().\L.) 

 dawsoni, with wliich it is associated in the shales of Manuels Brook. 



Formation and locality, — Middle Cambrian, shales on Manuels Brook, 

 Conception Bay, Newfoundland. It occurs abundantly with the Para- 

 doxides davisi fauna, and also in a band of shales 45 feet lower in the 

 section. 



Type.—^o. 27;U7, IJ.S.N.M. 



OBOLUS (LINGULELLA) FRANKLINENSIS, new species. 



Shell small, ovate, with the apex of the dorsal valve subacuminate; 

 convexity moderate. Surface of the shell marked by rather strong lines 

 and striie of growth, with very fine, slightly irregular, wavy stria; 

 between the coarser concentric stria;. Two ventral valves referred to 

 this species have a length of 3 and 3.5 mm., respectively, with a width 

 of about 2.75 mm. There are no dorsal valves in the collection. A ])ar- 

 tial cast of the interior of the shell carries an impression of radiating 

 stria', and a strong cast of a narrow pedicle furrow, and a few concen- 

 tric lines of growth. 



OhHcmatioua. — This species is founded on three specimens of the ven- 

 tral valve that occur in the limestones interbedded in the dark shales 

 above the Lower Cambrian Olenellus bearing shales. A larger shell 

 has the same surface characters and occurs at the same relative 

 geologic horizon, and it may belong to this species. The only speci- 

 men of it in the collection is apparently a dorsal valve. The exact 

 stratigraphic horizon has not been determined, but from the associated 

 species of AgnotitnH and Vtijchoparia it appears that the reference should 

 be to the Middle Cambrian. 



