522 CAMBKIAN BEACHIOPODA. 



, /- LiNGULELLA NiCHOLSONi Callawaj. 



Plate XXX, figures 3, 3a-f. 



Lingulella nicholsoni Callaway, 1874, Quart. Jour. Geol. Soc. London, vol. 30, p. 196. (JSlame proposed.) 

 Lingulella nicholsoni Callaway, 1877, idem, vol. 33, pp. 668-669, PI. XXIV, figs. 11, lla-b. (Described and discussed 



as below. Figs. 11 and lib are reproduced in this monograph, PI. XXX, figs. 3 and 3a, respectively.) 

 Lingulella nicholsoni Callaway, Davidson, 1883, British Fossil Brachiopoda, vol. 5, pt. 2, pp. 208-209, PL XVIl, figs. 



31, 31a, and 32. (The discussion of the species, the localities, and the figures given in the preceding reference 



are here copied.) 

 Lingulella nicholsoni Callaway?, Matley, 1902, Quart. Jour. Geol. Soc. London, vol. 58, pt. 1, p. 141. (A new locality 



mentioned.') 



The original description by Callaway follows : 



Ovate, depressed, widest about the middle, two-thirds as broad as long, front and sides rounded, beak moderately 

 acuminate, area of ventral valve striated, the stride parallel to the external slope of the valve, pedicle groove divided 

 by a narrow ridge down the middle; visceral surface pitted; exterior surface marked by fine concentric lines of growth. 



Length, 5 lines; width, 3.5 lines. 



This is a larger shell than Lingulella ferruginea Salter and its sides are not so parallel. 

 It closely resembles L. lepis (Salter); but L. lepis is wider toward the front, according to 

 Davidson's figures [1883, PI. XVII, figs. 31, 31a, and 32]. 



In a collection kindly lent to me by Dr. Charles Lapworth I found this species to vary 

 greatly in outline in the shales. It is a well-marked species. Plate XXX, figures 3b and 3c, 

 shows probably the most characteristic adult forms. 



The specific name was given in honor of Mr. Nicholson. 



Formation and locality. — Tipper Cambrian: (3041 [Callaway, 1S77, p. 669]) Shineton shales at Shineton, Mary 

 Dingle, Dryton, Cressage, 1 mile (1.6 hm.) ivest of Cressage, west of Harley, and under Cound-Moor quarry; and (3041s 

 [Davidson, 1883, pp. 208 and 209]) Shineton shales at Bull Hill Cottage and Pewardine; all in South Shropshire, 

 England. 



(3041) In the collection received from Dr. Charles Lapworth, collected by R. R. Rhodes, of the Geological 

 Survey of Great Britain, the species is recorded in shales at the following localities: 2246, 2481, 2499, 2512, 2513, 

 2541, 2548, 2556, 2567, 2625, and 2627, all on Shineton Brook and vicinity. South Shropshire, England. 



(304a [Groom, 1902, p. 110]) "Bronsil shales;" and (304b [Groom, 1902, p. 109]) lower part of the "^^Tiite Leaved 

 Oak shales" (the zone of Polyphyma); both in the Malvern Hills, between Herefordshire and Worcestershire, England. 



, Lingulella ora (Walcott). 



1/ 



Plate XXXV, figures 9, 9a-d. 



Obolus (Lingulella) orus Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 330. (Characterized as below as a new 

 species.) 



This is a shell of the Lingulella manticula (White) form, but differs from it in being more 

 elongate; ventral valve more acuminate and dorsal valve proportionately larger. Its nearest 

 allies in form are among the group of narrow, elongate shells occurring in New Brunswick 

 and Cape Breton. It differs from all of them — Lingulella coUicia (IMatthew), L. fiumenis (IMat- 

 thew), L. cama (Walcott) , etc. — in haviag a thick, strong shell and usually more acuminate 

 dorsal valve. The exterior surface bears rather strong concentric lines of growth and very 

 fine, irregular, undulating, elevated strife that suggest the surface of Oholus (Westonia) ella 

 (Hall and Whitfield) when seen in reflected light with a strong magnifier. 



This Httle shell occurs abundantly, but good interiors have not been found. The maia 

 vascular sinuses appear to be submarginal in both valves, and the visceral area of the dorsal 

 valve narrow, extending a little beyond the center of the valve. 



Formation and locality.— Tipper Cambrian: (9p) About 160 feet{4S.S m.) above the porphyry contact in the 

 limestones of the Reagan sandstone, in SE. i NE. i sec. 2, T. 4 N., R. 13 W.; and (9ci) about 10 feet (3 m.) above 

 the porphyry contact and 90 feet (27.4 m.) below the Arbuckle limestone, in limestones of the Reagan sandstone, 

 in middle of west half of sec. 2, T. 4 N., R. 13 W.; both about 15 miles (24.2 km.) northwest of Fort Sill, Comanche 

 County, Oklahoma. 



