556 CAMBRIAN BRACHIOPODA. 



collected by S. Ward Loper from the same beds from which the types of L. (L.) longinervis 

 came, the surface is indistinguishable from that of L. (L.) gregwa. 



Matthew [1903, p. 134] considers the long, large "visceral callus" of the dorsal valve as the 

 most prominent characteristic of this form. I find in L. (L.) gregwa (Matthew) and L. (L.) 

 exigua (Matthew) that the visceral area in many specimens extends nearly to the front of the 

 dorsal valve and that the length and strength of the visceral area in both ventral and dorsal 

 valves of Lingulepis are not usually characters to be depended upon as criteria for specific 

 determinations. The position assigned to the central and anterolateral muscle scars by Matthew 

 [1903, PI. VII, figs. 6e and 6f] appears to be theoretical, as a most careful study of the typ- 

 ical specimens fails to locate them as indicated in the figures. In fact, the specimens are too 

 poorly presei'ved to indicate clearly where the scars are. Fine casts of the interior collected 

 by Loper show the scars named farther toward the central portion of the shell. 



Lingulella (Lingulepis) longinervis differs from L. (L.) exigua (Matthew) in its less atten- 

 uate ventral valve and less robust character in both size and thicloiess of shell. 



The specimens collected by Matthew are small and do not show the variation that exists 

 in the collection made by Loper. In a laj'^er of reddish brown sandstone Loper found a great 

 number of shells varying in size and form from those similar to Matthew's tj^pes to shells nearly 

 twice as large. In a layer of hard gray standsone, 5 feet above, all the specimens are similar in 

 size and form to those collected by Matthew. Lingulella triparilis (Matthew) occupies a 

 position intermediate in form between L. (L.) gregwa (Matthew) and L. {L.) longinervis, and 

 the surface characters of the three species are essentially of the same type. 



Formation and locality. — Middle Cambrian: (372f) shales of unknown stratigraphic position; (13d'') sand- 

 stones 10 feet (3 m.) below Division E2a; (13g) sandstones 10 feet (3 m.) above Division E2a; (13f) sandstone 20 feet 

 (6 m.) above Division E2a; (13p and 13p0 sandstones 40 to 45 feet (12.2 to 13.6 m.) above Division E2a; (13d) sand- 

 stones opposite the thii-d waterfall in Dugald Brook, between Divisions E2a and E2b; (lOp) sandstones just below the 

 waterfall, in Division E2b; (3440 [Matthew, 1903, p. 134\) sandstones of Division E2h; and (131) shaly sandstones of 

 Division E3a; all in Matthew's [1903, p. 21] Etcheminian, on Dugald Brook, Indian River, eastern Cape Breton, Nova 

 Scotia. , I 



(lOp') Sandstone one-fourth mile (0.4 km.) from lower bridge, on Gregwa Brook, Indian River; and (lOp") sand- 

 stone on the small brook on the hill between the bridge over Indian River and McPhees Brook; both in eastern Cape 

 Breton, Nova Scotia. 



Lingulella (Lingulepis) pumila (Matthew.) 

 (/ 



Plate XLV, figures 3, 3a. 



Lingulepis pumila Matthew, 1903, Geol. Survey Canada, Rept. Cambrian Rocks Cape Breton, p. 7.5, PI. VII, figs. 



5a and 5b. (Described as a new species. The specimens represented by figs. 5a and 5b are redrawn in this 



monograph, PI. XLV, figs. 3 and 3a, respectively.) 



This species differs from Lingulella tripiarilis (Matthew) and Lingulella {Lingulepis) gregwa 

 (Matthew) in having a more attenuate ventral valve. In this respect it resembles the narrow 

 forms of L. (L.) longinervis (Matthew). The material is poor, so that only the general form 

 can be used to characterize it. One dorsal valve shows that the shell was thick, very much as 

 in L. (L.) exigua (Matthew). The surface of exfoliated shells is nearljr smooth. Matthew 

 [1903, p. 75] describes the outer surface as consisting of irregular concentric ridges, about six in 

 the space of a millimeter. 



Formation and locality. — Middle Cambrian: (344f [Matthew, 1903, p. 72]) Shales in the Coldbrook terrane of 

 Matthew, on Dugald Brook, Indian River, eastern Cape Breton, Nova Scotia. 



Specimens that are somewhat doubtful!}^ referred to this species occur at the following 

 locality : 



Middle Cambrian: (13k) Shales of Matthew's [1903, p. 15] Coldbrook, above the great fall in Dugald Brook, Indian 

 River, eastern Cape Breton, Nova Scotia. 



Lingulella (Lingulepis?) pygm^a (Salter). 



Plate XXX, figure 10. 



Lingula pygmsea Salter, 1865, Quart. Jour. Geol. Soc. London, vol. 21, p. 102, figs. 8a and 8b, p. 101. (Described as a 

 new species; see p. 557 for copy. Figs. 8a-b are copied in this monograph, PL XXX, fig. 10.) 



