482 CAMBRIAN BRACHIOPODA. 



Observations . — This fine species occurs in great abundance in the upper beds of Little Belle 

 Island associated with a narrow form of Lingula; and also in the higher beds on Great Belle 

 Island, and a little below the layers carrying Oholus (Lingulololus) affinis (Billings) and 0. (L.) 

 spissus (Bilhngs). The species is found at some little distance above the horizon in which I 

 collected a species of Olenus and I refer the horizon to the Ordovician or the passage beds to 

 the Ordovician fauna. 



The species appears to be clearly distiiict from any described form. It may be compared 

 with Lingulella davisi (McCoy) in relation to its size and outline, but not in other respects. 

 It differs in the size and position of the muscle scars and the more strongly punctate interior 

 surface. Some of the smaller shells closely resemble Lingulella concinna Matthew and the 

 larger ones L. lens (Matthew). When studying the material of the two latter forms in 1901, 

 I referred them all to Lingulella bella [Walcott, 1901, p. 685], but with the large series now 

 before me this reference is not sustained. 



Formation and locality. — Lower Ordovician: (114b) Sandstone 1 mile (1.6 hm.) north of Lance Cove, Great Belle 

 Island, Conception Bay, Newfoundland. 



Upper Cambrian : (114 and 114a) Uppermost sandstone beds and the sandy shales underlying them on Little Belle 

 Island, in Conception Bay, Newfoundland. 



(343b) Limestone pebble on Sachuset Beach, near Newport, Narragansett Bay, Rhode Island. 



Lingulella belltjla (Walcott). 

 -- Plate XIX, figures 1, la-e. 



Oholus {Lingulella) bellulus Walcott, 1898, Proc. U. S. Nat. Mus., vol. 21, p. 398. (Described and discussed as below, 



as a new species.) 

 Oholus {Lingulella) bellulus Walcott, Matthew, 1903, Geol. Survey Canada, Rept. Cambrian Rocks Cape Breton, 



p. 205. (Says this species and "Lingula hillingsana" Whiteaves are the same.) 



General form ovate with the ventral valve obtusely acuminate; dorsal valve round ovate; 

 valves moderately convex. Surface of shell marked by concentric lines of growth and exceed- 

 ingly fine, irregular striae that give the same appearance to the surface as that seen on Oholus 

 ( Westoniay ella (Hall and Whitfield) , Ololus fragilis (Walcott) , and on a larger scale on 

 Lingulella radula Matthew. The outer layer of the shell usually adheres to the arenaceous 

 matrix, leaving the shiny inner layer on the shell; this is marked by concentric striae and lines 

 of growth, and fine radiating strise. The shell is thin and formed of a very thin outer layer 

 and one or more thin inner layers or lameUse. 



The average length of the ventral valve is from 4 to 5 mm.; width, 3 to 3.5 mm. The 

 dorsal valves are a little shorter, 0.5 mm. to 1 mm. 



The cast of the area of the ventral valve shows it to be elongate, divided midway by a 

 narrow but strong pedicle furrow, and, about midway between the pedicle furrow and the 

 lateral margin, by a narrow flexure line; it is marked by strise of growth parallel to its base. 

 The area of the dorsal valve is not well shown on the specimens in the collection. 



The cast of the interior of the ventral valve shows somewhat imperfectly the visceral cavity, 

 but not the muscle scars. In an interior of the dorsal valve the main vascular sinuses (vs) 

 are well shown (PI. XIX, fig. Id), also the median septum (s). The central muscle scars are 

 faintly shown in one fragmentary interior of the dorsal valve. 



Observations. — This beautiful little species occurs in the arenaceous shales and thin-bedded 

 sandstones of Little Belle Island, in association with the larger species Lingulella bella (Walcott). 

 It is closely related to Lingulella ferruginea Salter, but differs somewhat in form and the more 

 anterior position of "the visceral cavity in the dorsal valve." The species is the Upper Cam- 

 brian representative of the Middle Cambrian species L. ferruginea. It occurs at about the 

 same horizon as L. billingsiana CV\^iiteaves) , but differs decidedly from it in form and convexity, 

 the only points of comparison which the material permits. 



Formation and locality. — ^TTpper Cambrian: (114 and 114a) <^ Uppermost sandstone beds and the sandy shales 

 underlying them on Little Belle Island, Conception Bay, Newfoundland. 



a Ilia is the type locality. 



