312 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 5/ 



Formation and locality. — Lower Cambrian (6ik) Mahto forma- 

 tion ; dark, hard siliceous shale ; northeast base of Mumm Peak above 

 Mural Glacier on west side of Hitka Pass, 6 miles (9.6 km.) in a 

 direct line north of summit of Robson Peak and northwest of Yellow- 

 head Pass, in western Alberta, Canada. 



LINGULELLA HITICA, new species 



Plate 50, figs. 1-3 



This species is represented by a number of compressed valves partly 

 flattened in the shale. The outer surface has concentric strise and 

 lines of growth, and the shell is built up of several layers of what was 

 probably calcareo-corneous material arranged as in typical Obolinse.'' 



The average size and appearance of the valves are shown by fig- 

 ure I, plate 50. A few ventral valves have a length of 13 mm., but 

 the average is about 10 mm. 



In outline of valves and general appearance, this species is similar 

 to Lingulclla hella (Walcott).^ It is so highly improbable that a 

 Lower Cambrian species of the Cordilleran sea could persist until 

 the close of Cambrian time in the Atlantic Province that I do not think 

 it advisable to identify the two widely separated forms as belonging 

 to the same species. 



There are no Lower Cambrian forms that seem to be similar to 

 L. hitka. 



The specific name is taken from the Indian name Hitka (brown), 

 a name applied to the mountain that rises on the east side of the ravine 

 in which the specimens of L. hitka were found. 



Formation and locality. — Lower Cambrian : (6ik) Mahto forma- 

 tion ; dark, hard siliceous shale ; northeast base of Mumm Peak above 

 Mural Glacier on west side of Hitka Pass, 6 miles (9.6 km.) in a direct 

 line north of summit of Robson Peak and northwest of Yellowhead 

 Pass, in western Alberta, Canada. 



OBOLELLA NUDA, new species 



Plate 52, figs. T,-7 



The first impression given by the shells of this species is that they 

 are closely allied to Oholella atlaiiiica Walcott.' They have about the 

 same size and form. They differ in having a flattened median space, 



^ Monogr. U. S. Geol. Survey, Vol. 51, 1912, p. 371. 

 ^ Idem, pi. 19, figs. 2, 2a-q; pi. 36, fig. 4. 

 " Idem, pi. 55, figs. I, la-i. 



