OBOLIDiE. 559 



from all other species known to me from the Cambrian rocks of the Grand Canyon region. 

 Oholus ( Westonia) chuarensis (Walcott) occurs in a layer of sandstone 50 or 60 feet higher up 

 in the section. 



Formation and locality. — Middle Cambrian: (74d) Sandstone beds in "Ton to" shale just above massive 

 sandstones near mouth of Bass Canyon, on the south side of the Grand Canyon of the Colorado, southeast of Powells 

 Plateau, Arizona. 



LiNGIILELLA (LlNGtJLEPIS ?) SQUAMOSA (Holl) . 



Plate XXX, figure 9. 



Lingula squamosa Holl, 1865, Quart. Jour. Geol. Soc. London, vol. 31, pt. 1, p. 102. (Described as a new species; 



see below for copy.) 

 f Lingula squamosa Holl, Davidson, 1866, British Fossil Brachiopoda, vol. 3, pt. 7, No. 1, p. 41, PL II, fig. 7. (Copies 

 ■ the original description and discusses species. Fig. 7 is copied in this monograph, PL XXX, fig. 9.) 



The original description by Holl follows: 



Triangular, broad anteriorly, compressed; beak acute; anterior margin truncate; shell thick, strongly grooved 

 from side to side by imbricating lines of growth. Length, one-fourth inch. In the light-brown felspathic sandstone 

 of the Hollybush series. 



The sandstone of the Hollybush series is beneath the Black shales in which Lingulella 

 (Lingulepisf) pygmsea (Salter) occurs, but appears to form a portion of the Upper Cambrian 

 of the Malvern Hills section. The species has a peculiar cuneate form, more like that of L. (L.) 

 acuminata (Conrad) than any other European shell known to me. On this account it is 

 referred to the subgenus Lingulepis. 



Formation and locality. — Upper Cambrian: (3042 [Holl, 1865, p. 102]) Sandstones of the Hollybush series, 

 Malvern Hills, between Herefordshire and Worcestershire, England. 



Lingulella (Lingulepis) starri (Matthew). 



Plate XXXVII, figures 2, 2a-b. 



Lingulella starri Matthew, 1891, Trans. Roy. Soc. Canada for 1890, 1st ser. vol. 8, sec. 4, No. 6, pp. 146-147, PI. XV, 

 figs. 5a-c, 6a-b. (Described and discussed as a new species. According to Matthew the type specimens have 

 been mislaid or lost, and the specimens represented in this monograph are from new material collected by him.) 



Lingulepis starri Matthew, 1903, Geol. Survey Canada, Kept. Cambrian Rocks Cape Breton, p. 195. (Mentioned.) 



General form cuneate, elongate ovate, with the ventral valve obtusely acuminate and the 

 dorsal valve broadly ovate; valves appear to have been moderately convex. Outer surface 

 of the shell marked by fine, concentric, shghtly irregular strise, 8 to 12 in the space of a milli- 

 meter; when the outer layer of shell is exfoliated coarser concentric strias are seen; and on 

 the inner surface of the shell strong concentric striae and numerous radiatiag strise occur, the 

 latter being most prominent on the anterior half of the valves. The shell is strong and is buUt 

 up of a thin outer layer and several inner layers or lamellae, very much as in Lingulella acutan- 

 gula (Roemer). 



A large ventral valve, as measured by Matthew, has a length of 16 mm.; width, 14 mm. 



A cast of the interior of a broken ventral valve shows the visceral cavity (v) and a trace 

 of the main vascular sinus (PI. XXXVII, fig. 2b). 



Observations. — This is one of the large species of the genus and compares in this respect 

 with Lingulella ampla (Owen) and Oholus ( Westonia) aurora (Hall) . Matthew wrote me that 

 the type of this species had been mislaid or lost. The illustrations are taken from other speci- 

 mens identified and labeled by Mm. 



The specific name was given in honor of Mr. R. P. Starr, who discovered the species. 



Formation and locality. — TTpper Cambrian: (308c [Matthew, 1891, p. 147]) Shales of Division $h of Matthew's 

 Johannian at St. John; and (2x) thin-bedded sandstones of Division 2 of Matthew [1892, p. 59], on the south shore 

 of Long Island, Kennebecasis Bay [Matthew, 1898a, pp. 124 and 127]; both in St. John County, New Brunswick. 



