April 28, 1916] 



SCIENCE 



607 



NOTES ON CANADIAN STRATIGRAPHY 

 AND PALEONTOLOGY. I 



Cordilleran Province 



In 1911 and 1912 Dr. K. A. Daly carried on 

 geological studies along the line of the Ca- 

 nadian Pacific railway between Golden and 

 Kamloops, British Columbia, a distance of 

 224 miles. A preliminary statement of re- 

 sults was published in Guide Book No. 8 of 

 the International Geological Congress and the 

 complete report has recently become avail- 

 able.^ The transverse section of the eastern 

 half of the Canadian Cordillera thus made 

 known roughly parallels the International 

 Boundary section and is about 120 miles north 

 of it. 



Three major geological provinces are recog- 

 nized. The first of these is that underlain in 

 the main by the Shuswap terrane and includes 

 a portion of the Selkirks and the northern 

 half of the Columbia mountains. The Shus- 

 wap rocks are of "Early Pre-Cambrian " age 

 and consist of metamorphosed sediments and 

 volcanics, aggregating over 28,000 feet in 

 thickness, intruded by innumerable sills and 

 laccoliths of granite as well as by batholithic 

 masses of the same plutonic rock. The whole 

 is essentially a very large mass of ideal crys- 

 talline schists, the result of static metamor- 

 phism. The author very properly makes a 

 distinction between recrystallization which re- 

 sults from deep burial and that accompanying 

 erogenic movement. The former he terms 

 static or load metamorphism, restricting the 

 term dynamic metamorphism to the latter 

 phase. In the alteration of the Shuswap ter- 

 rane both contact and dynamic metamorphism 

 have played minor parts. 



Unconformably overlying the Shuswap 

 schists on the east is an enormous mass of 

 bedded rocks belonging to the Beltian and 

 Cambrian systems. These make up the greater 

 part of the Purcell and higher Selkirk moun- 

 tains. The Belt series consists of quartzites, 

 limestones, and metargillites attaining a thick- 



i"A Geologieal Eeconnaissanee between Golden 

 and Kamloops, B. C, along the Canadian Pacific 

 Eailway," K. A. Daly, Geological Survey, Can- 

 ada, Memoir 68, 1915. 



ness of 32,750 feet and is overlain by 7,Y50 

 feet of quartzite referred to the lower Cam- 

 brian. No evidence of unconformity between 

 the Beltian and Lower Cambrian was ob- 

 served. The clastic sediments of these series 

 were derived in the main from the erosion of 

 the Shuswap terrane. The absence of ripple 

 marks and mud cracks leads to the conclusion 

 that most of the Beltian-Cambrian sediments 

 in the region traversed are off-shore deposits. 

 No horizons of playa or flood-plain sediments 

 were identified. Much of the finer quartz silts 

 are believed to have originated as wind-borne 

 dust, blown out to sea. The limestones are 

 interpreted as chemical precipitates resulting 

 from the bacterial decay of animal matter. 

 Extrusive lavas are in some places interbedded 

 with the sediments. The entire series has 

 been moderately metamorphosed and its struc- 

 ture is that of a great synclinorium nearly 

 forty miles broad. East of the Purcell range 

 the Columbia Eiver valley is believed to be 

 underlain by Upper Cambrian and Ordovician 

 beds which have been faulted into contact 

 with the Beltian formations. 



West of the Shuswap terrane, Beltian and 

 early Paleozoic rocks are absent, and the upper 

 Paleozoic and younger formations are believed 

 to rest on the pre-Cambrian complex. This 

 constitutes the province of the Interior Pla- 

 teaus. Its geology is allied to that of the Coast 

 and Vancouver ranges as it is in the western 

 geosynclinal belt of the Cordillera, which 

 forms a strong contrast to the eastern belt. 

 Until the close of Mississippian time the west- 

 ern belt was in the main a land surface, while 

 in the eastern belt sedimentation was in prog- 

 ress. Structural complexity here is of a high 

 order. At the base is the Cache Creek series, 

 13,700 feet of limestone and elastic sediments, 

 of probably Pennsylvanian age. Unconform- 

 ably overlying this series are the conglomer- 

 ates, breccias, sandstones, and massive lavas 

 of the Nicola series. This has an estimated 

 thickness of 5,300 feet and is referred to the 

 Triassic and Jurassic periods. The youngest 

 bed-rock formation in the area is a thick mass 

 of Tertiary volcanics with interbedded sedi- 

 ments, which is believed to be of Oligocene 

 age. 



