no. 5 pre-devonian paleozoic formations 365 



McNaughton Formation p^^^ ^^^^^^ 



I. Quartzitic sandstones 500 + 1524 + 



Total Lower Cambrian 3,900 + 1,188.7 + 



Total thickness, Cambrian sediments 11,300 3,444-2 



Total thickness of section i3,30o 4.053-8 



Unconformity 



PRE-PALEOZOIC SECTION 



ALGONKIAN 



BELTIAN SERIES 



MiETTE Formation 



I. Massive gray sandstones, with interbedded siliceous 



shales 2,000 + , 609.6 -\- 



Base concealed. 



Lake Kinney Section 

 A diagrammatic outline sketch, made July 13, 1913, of a north- 

 eastern and southwestern section crossing the southeastern half of 

 Lake Kinney is here reproduced ; also one of a northwestern and 

 southeastern section through the massif of Robson Peak. (See figs. 



34, 35-) , 



As previously mentioned, the limestones at the west base of Robson 

 Peak are superjacent to Lower Cambrian sandstones at the head 

 of Lake Kinney (3,220 feet, 981.5 m.), and Middle Cambrian fossils 

 occur in the limestones 600 feet (182.9 ""'•) above the sandstones at 

 the southeast end of the lake. The dip of the limestones northeast 

 under the mountain carries the contact with the sandstones deeper 

 directly beneath the apex of the peak, but just how much is unknown, 

 as the synclinorium flattens out more or less beneath the mountain. 

 Berg Lake is 2,160 feet (658.4 m.) above the level of Lake Kinney, 

 and to this we add 1,600 feet (487.7 m.) to obtain the thickness up 

 to the level where L. D. Burling found a few Middle Cambrian 

 (Stephen) fossils. This would give a thickness of 3,760 feet (1,146. 

 m.) for the Middle Cambrian limestones, to which there probably 

 should be added two or three hundred feet (60.9 or 91.4 m.) to carry 

 the section up. to the base of the Upper Cambrian. There then re- 

 mains a thickness of 5,600-f feet (1,706.9-1- m.) of Hmestones to the 

 summit of the peak. The only unbroken reliable section of the Upper 

 Cambrian is that of Burling for lyatunga Mountain (p. 366), which 

 has a thickness of about 3,000 feet (914.4 m.). Burling claims 5,000 

 feet (1,524 m.) for the Upper Cambrian, but that is obtained by 

 adding another section totally disconnected and without satisfactory 

 paleontological evidence. 



