NO. 5 PRE-DEVONIAN PALEOZOIC FORMATIONS I9I 



fossils from a dozen or more faunal horizons in the section, but noth- 

 ing- further is pubHshed by him in this or subsequent reports about the 

 collections or the section. 



During the season of 1921 a trail was completed under my direction 

 to the head of Ranger Brook into the heart of the Sawback Range, 

 and a carefully measured section made from the base of the Devonian 

 down through the Sarbach, Mons, Lyell, and Arctomys formations 

 to the Eldon. Fossils were collected and subsequently identified. 



In 1924, Dr. Kindle published a [laper entitled " Standard Palaeo- 

 zoic section of the Rocky Mountains near Banff, Alberta " ' in which 

 he follows Allan and includes in the estimated 3,700 feet ( 1,127.8 m.) 

 of the " Sawback limestone " the following geologic formations : One 

 Ordovician (Canadian), Sarbach;^ three Upper Cambrian, Sabine. 

 Lyell, and Arctomys ; and one Middle Cambrian formation, the Eldon, 

 which was identified by Allan through lithologic resemblance. 



I should prefer to use the term Sawback, but if we were .to give 

 only one formational name to every great limestone series as a matter 

 of convenience in mapping the areal geology, or for a sentimental rea- 

 son, I fear the history of the deposition of sedimentary formations in 

 the Cordilleran Geosyncline would be a most imperfect and misleading 

 one. It must be remembered that what appears on superficial exami- 

 nation to be the record of continuous deposition, may in reality be 

 a record imperfect and broken by great gaps caused by non-deposition 

 of one or more formations. Such unconformities occur in the pre- 

 Devonian limestone series of the Sawback Trough and must be taken 

 into account in identifying and naming the formations both of the 

 Sawback Trough and those that were deposited elsewhere during the 

 periods of non-deposition. In addition to the character of the strata 

 and their order of conformable or unconformable superposition, the 

 paleontological record should always be given careful consideration. 

 If that record shows in an apparently continuous series of beds that 

 there are faunas missing which occur in different formations or 

 systems elsewhere in well-established sections, then the geologist 

 should recognize that there are breaks in the stratigraphic record that 

 necessitate his searching for and finding the interruptions resulting 

 from non-deposition or erosion. When these are found he must 

 divide the apparently continuous series of strata into units or forma- 



' Pan-Amer. Geologist, Vol. XLII, No. 2, 1924, p. 15. 



"Kindle refers to the Sarbach as Walcott's Sarback formation, evidently 

 overlooking the fact that the name was derived from Mount Sarbach (10,700 

 feet, 3,261.4 m.) in the Glacier Lake District, where the formation has a thick- 

 ness of 1,120 feet (341.4 m.). 



