NO. 6 MIDDLE CAMBRIAN BRANCHIOPODA, ETC. 189 



The numerous small appendages projecting outside of the carapace 

 on the lower side indicate that the body had many segments and 

 appendages, but with only one specimen for study I shall not attempt 

 at this time to discuss it, as it is possible that other specimens will 

 be discovered during the field season of 1912. 



Formation and locality. — Middle Cambrian: (35k) Burgess shale 

 member of the' Stephen formation, on the west slope of the ridge 

 between Mount Field and Wapta Peak, one mile (1.6 km.) northeast 

 of Burgess Pass, above Field, British Columbia. 



CARNARVONIA, new genus 



The generic description is included with that of the type species. 



Genotype. — Carnarvonia venosa, new species. 



Stratigraphic range. — The stratigraphic range is limited to a band 

 of gray, buff-weathering siliceous shale forming the upper part of the 

 Burgess shale member of the Stephen formation. 



Geographic distribution. — On the slope of the ridge between Wapta 

 Peak and Mount Field, north of Burgess Pass, and about 3800 feet 

 above Field on the line of the Canadian Pacific Railway, British 

 Columbia, Canada. 



The generic name Carnarvonia, is derived from Carnarvon, the 

 name of a mountain of the President Range, northwest of Field, 

 British Columbia, Canada. 



CARNARVONIA VENOSA, new species 



Plate 33, fig. I 



The figure on plate 33, of the two valves united and pressed flat on 

 the shale, illustrates all that is known of this genus and species. The 

 size and proportions are shown by the figure. 



The reticulated surface, adductor muscle scars, and vascular mark- 

 ings on the shell are beautifully shown on the specimen and in this 

 illustration. 



Formation and locality. — Middle Cambrian : (-^SiLj Burgess shale 



10 



member of the Stephen formation (about 75 feet (22.8 m.) above 

 the phyllopod bed near the base of the shale), on the west slope of 

 the ridge between Mount Field and Wapta Peak, one mile (1.6 km.) 

 northeast of Burgess Pass, above Field, British Columbia. 



