584 CAMBRIAN BRACHIOPODA. 



of the posterior margins of the shell; in others it has the outhne of a slightly convex pseudo- 

 deltidium. 



Observations. — This species in its reticulate surface ornamentation recalls Micromitra 

 (Iphidella) fannula (Wliite) and Mickwitzia monilifera (Linnarsson). In form the young 

 shells are not unlike Kutorgina cingulata (Billings). A large, imperfect, ventral valve, 24 by 

 24 mm., of this genus, was collected by J. E. Clayton from the Cambrian limestone of the 

 Silver Peak district. It may belong to K. perugata, and it is so referred for the present. From 

 the shales of the Olenellus zone in Silver Canyon, Wliite Mountain Range, a series of com- 

 pressed specimens was collected. Some of these show a concave pseudo-area on the ventral 

 valve, also strong main vascular sinuses. Some of the shells from the shales of Locality 175 

 have lost all traces of surface characters, only a faint, smooth impression remaining. 



Formation and locality.— Lower Cambrian: (313i) Limestone collected at long. 117° 20' W., lat. 38° N., in 

 the western part of Esmeralda County, Nevada. 



(Iv) Shales of No. 3 of the Silver Peak group, Barrel Spring section [Walcott, 190Sf, p. 1S9], 3 unites {4-8 km.) 

 north of Valcalda Spring and 4 miles {6.4 km.) west-northwest of the Drinkwater mine; (175) « shales carrying Olenellus 

 on the divide between Clayton and Fish Lake valleys, about 1.5 miles (24.2 km.) south-southwest of the town of 

 Silver Peak; and (184) shales at the summit of the Silver Peak Range, 10 miles (16.1 km.) southwest of the town of 

 Silver Peak; all in the Silver Peak quadrangle (U. S. Geol. Survey), Esmeralda County, Nevada. 



(7) Shaly beds about 1,000 feet (305 m.) above the quartzitic beds. Silver Canyon, White Mountain Range, 

 Inyo County, California. 



Kutorgina sardiniaensis Walcott. 



Plate V, figures 4, 4a-c. 



Kutorgina cingulata Bornemann [not (Billings)], 1891, Nova Acta Acad. Cajs. Leop.-Carol. Germanicte Natura Curio- 

 sorum, Bd. 56, No. 3, p. 440, PI. XIX (XXXIV), figs. 22 and 23. (Described and discussed in German; see below 

 for translation. Figs. 22 and 23 are copied in this monogi'aph, PL V, figs. 4b and 4c, respectively.) 



Lingula rouaulti Bornemann [not Salter], 1891, idem, p. 439, PL XIX (XXXIV), fig. 21. (Characterized and dis- 

 cussed in German. Fig. 21 is copied in this monograph, PL V, fig. 4.) 



Kutorgina sardiniaensis Walcott, 1901, Proc. U. S. Nat. Mus., vol. 23, p. 695. (Merely changes specific reference of 

 Bornemann's Kutorgina cingulata.) 



Kutorgina sardiniaensis Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 311. (Original description, Bornemann, 

 1891, p. 440, translated as below and species discussed as below as a new species.) 



The original description by Bornemann follows : 



Transversely oval, more or less arched, with a straight margin which is a little shorter than the greatest breadth 

 of the shell. Surface shows strong concentric lines of growth. 



Found quite commonly in the slates with Olenopsis and Metadoxides near Canal Grande, and rarely in sandstone 

 with Archxocyathus on Punta Pintau. The specimens in the argillaceous shale are always pressed very flat, and are 

 imperfect; in the sandstone, impressions of the outer surface are often found. 



Here belongs, perhaps, also the shell designated above as Lingula rouaulti (?). 



All that is known of the species is represented by the illustrations. It appears to be con- 

 generic with Kutorgina cingulata (Billings), but not siiecifically identical with it. 



Formation and locality. — Middle? Cambrian: (354) Yellowish-brown slates not far from the buildings of Canal 

 Grande; (354b) yellowish sandstone with Archxocyathus at Punta Pintau and elsewhere; and (354e)6 slate at Porto 

 Canal Grande; all [Bornemann, 1891, pp. 439 and 440] in the island of Sardinia, Italy. 



Kutorgina sp. undt. Walcott. 



Kutorgina sp. undt. Walcott, 1905, Proc. U. S. Nat. Mus., vol. 28, p. 311. (Characterized and discussed as below 

 as an undetermined species.) 



Ventral valve transverse, moderately convex; length, 6 mm.; Avidth, 8 mm.; pseudo-area 

 short and sloping beneath the apex at an angle of about 45°. 



A single cast from a coarse sandstone is all that is known of tliis species. It may be a young 

 shell of K. cingulata (Billings), but the means of comparison do not justify such a reference. 



Formation and locality. — Lower Cambrian : (47a) Sandstone on the southwest side of Sailings Mountain, 2 

 miles (3.2 km.) east of Natural Bridge, Rockbridge County, Virginia. 



a The species is somewhat doubtfully identified from this locality. 



!> Specimens from this locality are in the collections of the United States National Museum. 



