'26 L. D. BURLING CAMBRO-ORDCVICIAX ^'EAR MOUXT ROBSOX 





Feet 





Feet 



Tah formation ( § 32) 



800 



Mural limestone formation 





Siliopoim *s]ifilp siTifl infpr- 





( s .32 ) 



1.000 



bedded siliceous 1 i m e- 





Massive arenaceous lime- 





stoues. 





stones with interbedded 

 shales and quartzitic 

 sandstones. 

 Thickness in Mnmm I'eak. 





Thickness in Tah Peak. 





Fossils : Abundant at many 





Fossils : None. 





horizons, the "new Lower 

 Cambrian subfauna"' oc- 

 curring 550 feet below 

 top (§32e). 





MrXauf/htou SfDidstoucs 



500 



Unnamed sandstones ( § 33 ) . . 



400 



Thickness in Yellowhead 





Thickness in Mumm Peak. 





Pass (§33). 





base concealed. 





Fossils : None. 





Fossils : None. 





Total Lower Cambrian 



3,900 



'otal Lower Cambrian 



2.600 



Total Cambrian 



12,200 



'otal Cambrian 



12.500 



1*re-Ca\ibrian : 





're-Camhria.x : 





Micttr sandstones (§34) 



2,000 



Not studied. 





Xo^VrEXCLATCRE AXD ThICKXESS OF FoRMATIOXS (§3) 



]\fr. Walcott described twelve fonnatiuns in his papers on the Mount 

 Robson region — ten from the region itself, one from the McXaughton 

 Mountains, and one from the Mictte liiver. Because of duplications and 

 changes in the interpretation of the stratigraphy in some of the moun- 

 tains, it has been necessary to reduce the number of these formations to 

 seven. The changes which have bjen required are expressed in the fol- 

 lowing table, in which there are sectional referencs to the detailed ex- 

 planations which occur in the text. The formations are listed in strati- 

 graphic order, reading from the top down (Table 1). 



IxcLUDED Fossils axd Age Relatioxships oe Fokmatioxs (§-!:) 



The main differences in the formations and fossil horizons listed by 

 Walcott and the writer are (a) the discovery of thin-bedded Ordovician 

 limestones and shales above the Lynx instead of the Eobson limestones, 

 and (b ) the reference of the Xew Lower Cambrian subfauna. a horizon 

 referred by AValcott to the "Hota," Init found by the writer in the *''Tah*' 

 (Table 2). 



XOMEXCLATURE OE MOUXTAIXS AXD RoCKS EXPOSED IX EACH 



FORMATIOX (§ 5) 



Mr. A\'alcott has made several cluinges in or additions to the names 

 applied to the topographic features of the Mount Robson reaion by the 



