L. D. Burling — The Albertella Fauna. 171 



Attention should be called to the apparent agreement in the 

 thinning of the formations to the eastward ; but changes in 

 sedimentation in the Canadian Pacific Railway section are so 

 frequent and important that measures of thickness are usually 

 local only in their application. 



In 1914: 3 I did not presume to question Walcott's reference 

 of the Albertella fauna to the Mount Whyte formation, indeed 

 the writer's assignment of that fauna to the Middle Cambrian 

 necessitated a change in the systemic reference of the Mt. 

 Whyte formation. I am now as thoroughly convinced that all 

 but the lowest beds of the Mt. Whyte formation are Middle 

 Cambrian in age, but the discovery that the Albertella fauna 

 occurs in a shale member embedded 375 feet up in the over- 

 lying massive arenaceous limestones of the Cathedral formation 

 robs me of one of the main arguments which I used in 1914 

 for the Middle Cambrian age of the Mt. Whyte. 



The reported discoveries of the Albertella fauna to date are 

 as follows, recording them in the order of their discovery : 



1. Gordon Creek, 6 "miles from the south fork of Flathead 

 River, Ovando quadrangle (U. IS. G. S.), Powell County, Mon- 

 tana, in a shale 75 feet above a quartzitic sandstone (1905). 4 



2. Mount Bosworth, British Columbia, in drift near railroad 

 right of way between Hector and Stephen (1907). 6 



3. Mount Stephen, British Columbia, 200 feet above the 

 quartzitic sandstones of the St. Piran formation (1907). ° 



4. Lake Agnes section, near Lake Louise, Alberta, in a shale 

 correlated with the horizon on Mount Stephen, No. 3 (1907). 7 



5. Liautung, Manchuria, on the shore of Tschang-hsing-tau 

 Island (1909)." The correlation of this species with Albertella is 

 somewhat doubtful, but it occurs above well marked Middle Cam- 

 brian horizons. 



6. Mt. ltobson region, British Columbia, 550 feet above the 

 base of the Chetang limestones (1912).'' 



7. Elko, British Columbia, in the Burton formation (191 3). I0 



8. North Kootenay Pass, British Columbia, in shale (1915). " 



9. Mount Bosworth, British Columbia, the horizon of the 

 drift blocks mentioned in " 2" found interbedded in the massive 

 limestones of the Cathedral formation 375 feet above its base 

 (1915). 12 



10. Castle Mountain, Alberta, at the same horizon as the one 

 on Mount Bosworth (1915). 13 



11. Mount Robson region, British Columbia, in a limestone 

 whose exact stratigraphic relations have not yet been worked out. 

 The horizon is comparable, however, with that on Mount Bos- 

 worth (1915). 14 



The genus Albertella has been figured by Walcott in the 

 following publications: Smithsonian Misc. Coll., vol. liii, 1908, 

 plates 1 and 2 ; and Research in China, vol. iii, 1913, plate 12, 



