374 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 64 



In the arenaceous shale of locaHty 746 (about 100-120 feet above 

 the horizon of locahty 74) I found 



Obolus (IVestonia) chuarcnsis Walcott 



Eocystites ? undt. species 



Hyolithes 



Alokistocare althca Walcott 



Dolichometopus productus (Hall and Whitfield) 



Dolichomctopus tontoensis Walcott 



Formation and locality. — Middle Cambrian: (746) Bright Angel 

 shale 100 feet (32 m.) above Tapeats sandstone. On west side of 

 Cameron trail about 0.5 mile (0.8 km.) north of Indian Garden 

 Spring, south side Grand Canyon of Colorado River, Coconino 

 County; and (74) Tapeats sandstone; about 300 feet (91.4 m.) 

 above its base, at the head of Nunkoweap Valley, Grand Canyon of 

 the Colorado River, both in Arizona. 



HOUSIA, new subgenus 



This form is distinguished from Dolichomctopus by its small pal- 

 pebral lobe, absence of genal spine on free cheek, form of termina- 

 tion of pleural lobe of thoracic segments, and outHne of normal 

 form of pygidium. Surface unknown. Fragments of the only 

 species referred to Housia indicate a length of 7.5 to 8 cm. 



Genotype. — Dolichometopus {Housia) varro Walcott. 



The one species now referred to Housia is from the central portion 

 of the Upper Cambrian in the House Range of western Utah. 



DOLICHOMETOPUS (HOUSIA) VARRO, new species 

 Plate 65, figs. I, la-e 



The general characters of this species have been given in connec- 

 tion with the subgenus Housia. Only otie specimen of the cranidium 

 was found, although 11 free cheeks and five pygidia were collected. 

 That it. was a fairly large species is shown by a thoracic segment 

 40 mm. in length and several large free cheeks. 



Formation and locality. — Upper Cambrian : (30 1) Orr formation ; 

 about 2,790 feet (860 m.) above the Middle Cambrian and 1,900 feet 

 (579.1 m.) below the top of the Upper Cambrian, in shales forming 

 ih of the Orr formation ^ on Orr Ridge, about 5 miles (8 km.) south 

 of Marjum Pass; also (soy) in slightly metamorphosed shales sup- 



Smithsonian Misc. Coll., Vol. 53, 1908, p. 176. 



