3IO SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 5/ 



Peak, which is a high point (9,740 feet = 2,968 m.) directly north of 

 Robson Peak. The blocks of shale falling- from the cliff had been 

 carried out and down the ice of Mural Glacier. The glacier also 

 passes over the cliff of shale for half a mile to the west. We reached 

 the glacier by climbing up over the cliffs of Mural Brook, which 

 enters Smoky River about a mile (1.6 km.) below the mouth of Calu- 

 met Creek. From the foot of the glacier it is about two miles 

 (3.2 km.) up to the base of Mumm Peak. A better way to go is to 

 climb up the mountain side 2,000 feet and cross Hitka Pass, a divide 

 between Mumm Peak and Hitka Mountain. The locality is high up 

 where rain, fog, and snow squalls may be expected nearly every day 

 of the year. 



The fauna includes the species described in this paper, also a species 

 of PlanoUtcs (annelid trail), Cystid ? sp. undt., Hyolithes sp. undt.. 

 and Hymcuocaris sp. undt. These, with the new species, make up a 

 subfauna in the upper portion of the Lower Cambrian that has not 

 been found elsewhere. It is marked by the absence of Olcnelliis 

 canadensis Walcott and Protypns fieldensis Walcott, the typical forms 

 of the upper part of the Lower Cambrian section along Kicking Horse 

 Pass. 



There is undoubtedly a larger fauna to be obtained from the 

 Oleiiellus trucmani zone, but to find it will require a camp near the 

 locality on Hitka Pass and thorough collecting under adverse 

 conditions. 



DESCRIPTION OF SPECIES 

 MICKWITZIA MURALENSIS, new species 



Plate 50, figs. 10, II ; plate 51, figs. 1-6; plate 52, fig. i 

 This species differs from Mickzvitzia monilifera Linnarsson ^ in 

 having a less elevated apex on the ventral valve, a varying position 

 of the apex, and in being in general more transverse. 



The shell is built up of several layers or lamellae that give it thick- 

 ness and strength. The outer surface is fairly well shown by figure 6, 

 plate 51. It is formed of fine, concentric, minutely undulating and 

 inosculating ridges that are crossed by low, irregular radiating 

 ridges. There is also a pitted appearance resulting from the hollows 

 between the ridges. On many shells there appear to be true punctje 

 that penetrate through the outer layer of the shell. The inner layers 

 are marked by fine concentric and radiating lines. 



Monogr. U. S. Geol. Survej^ Vol. 51, 1912. pi. 6, figs, i, la-n. 



