486 



CAMBRIAN BRACHIOPODA. 



The exterior surface is marked by very fine concentric striae or fine ridges of growth; 

 numerous radiating strise occur on the inner layers of the shell. Nothing is known of the interior 

 of either valve. 



The specific name is given in honor of Prof. J. M. Clarke, of Albany, New York. 



FiGUEE i2.—Lingulella clarTcei n. sp. A, A', Exterior and side outline of ventral valve (U. S. Nat, Mus. Cat. No. 51853a). B, Exterior of ventral 

 valve, the type specimen (U.S. Nat. Mus. Cat. No. 51863b). C, Broad form of dorsal valve (U. S. Nat. Mus. Cat. No. 51853c). D, Dorsal valve 

 with exterior layer of shell exfoliated (U. S. Nat. Mus. Cat. No. 52458a). 

 The specimens represented by figures 42A, 42B,and 42C are from Locality 58; that represented by flgm"e42D is from Locality 60; both in Nevada. 



Formation and locality. — Middle Cambrian: (60) Limestone in the upper beds of the Secret Canyon shale, 

 across the canyon from the dump of the old Richmond mine shaft; and (58) shaly limestones in the upper part of the 

 Secret Canyon shale, east side of New York and Secret canyons; both in the Eureka district [Hague, 1892, Atlas], Eureka 

 County, Nevada. 



LiNGULELLA coLLiciA (Matthew). 



u 



Plate XXXV, figures 1, la-f, 2, 2a-d. 



Leptobolus ? collida Matthew, 1899, Bull. Nat. Hist. Soc. New Brunswick, vol. 4, pt. 3, No. 18, p. 200, PL I, figs. 3a-e. 



(Described as a new species. Figs. 1, la-b, PL XXXV, of this monograph are drawn from three of Matthew's 



specimens, but closer identification is impossible.) 

 Obolus {Lingulella) collida (Matthew), Walcott, 1902, Proc. U. S. Nat. Mus., vol. 25, p. 610. (Characterized.) 

 Leptobolus collida Matthew, 1903, Geol. Survey Canada, Kept. Cambrian Rocks Cape Breton, pp. 112-113, PL VI, 



figs. 3a-e. . (Described and discussed. Figures copied from Matthew, 1899b, PL I, figs. 3a-e.) 

 Leptobolus collida collis Matthew, 1903, idem, pp. 114-115. (Characterized as a new variety.) 



This shell is associated with Lingulella atava (Matthew), but differs fi'om that species 

 in being larger and in having a more acuminate and broader ventral valve and more broadlj' 

 oval dorsal valve. The exterior surface is marked by very fine, slightly irregular, concentric 

 strise. The variety collis is simply a wide form, that is so closely united to L. collicia by many 

 gradations among the shells before me that I do not think it worthy of a distinct name. 



PoEMATioN AND LOCALITY. — Middle Cambrian: (lOp) Sandstones just below the waterfall in Division E2b; (13d') 

 sandstones opposite the third waterfall in Dugald Brook, between Divisions E2a and E2b; (344a [Matthew, 1903, 

 p. 26]) sandy shales of Division E3c; (13n')a saiidstones of Division £3 e; (344d [Matthew, 1903, p. 82]) sandy shales of 

 Division E3f; all in Matthew's [1903, p. 21] Etcheminian, Dugald Brook, Indian River, Cape Breton, Nova Scotia. 



(13m) Sandstones of Division E3f in Matthew's Etcheminian, Gillis Brook, eastern Cape Breton, Nova Scotia. 



(344e [Matthew, 1903, p. 78]) Shales of Division Eld of Matthew's Etcheminian, on Boundary Brook, eastern 

 side of the Escasonie Indian Reservation, eastern Cape Breton, Nova Scotia, Canada. 



Lingulella concinna Matthew. 

 Plate XXXIII, figures 2, 2a-h; Plate XXXIV, figures 1, la-r. 



Lingulella condnna Matthew, 1901, Bull. Nat. Hist. Soc. New Brunswick, vol. 4, pt. 4, No. 19, pp. 273-274, Pl.V, 

 figs. 2a-b. (Described and discussed as a new species. PL XXXIII, fig. 2d, of this monograph is drawn from 

 one of Matthew's specimens, but which one can not be determined.) 



Obolus {Lingulella) bellus Walcott (in part), 1901, Proc. U. S. Nat. Mus., vol. 23, p. 68.5. (Matthew's Lingulella 

 condnna is referred to, and described with Lingulella bella.) 



Obolus (Lingulella) concinnus (Matthew), Walcott, 1902, idem, vol. 25, pp. 608-609. (Described and discussed some- 

 what as on p. 487.) 



a 13n' is the type locality, though the specimens in the United States National Museum collections to which that number is assigned were 

 collected later than the type specimens. 



