CARBONIFEROUS UNDIVIDED. 391 



and volcanic products were laid down; while in its later stages the deposition of the limestone 

 must have been almost unbroken. The interlocking of the different classes of materials is such, 

 however, as to show the close connection which obtains between the Marble Canyon limestones 

 and the lower parts of the Cache Creek formation. * * * 



The extremely unsatisfactory condition of the rocks of the Cache Creek series for all pur-, 

 poses of measurement [is such that] in endeavoring to give some idea of the total volume of the 

 formation, no even . approximately correct data can be quoted. The subjoined summarized 

 section is therefore merely an attempt to indicate the general order of succession, and to some 

 extent the importance of the formation, in the western part of the area of the [Kamloops] map. 

 The order is descending. 



Feet. 



1. Massive limestones (Marble Canyon limestone), with some minor intercalations of volcanic 



rocks, argillites, and cherty quartzites. At least 1,000 feet seen in some single exposures. 

 Total thickness probably at least 3,000 



2. Volcanic materials and limestones, with some argillites, cherty quartzites, etc. Minimum 



thickness about 2,000 



3. Cherty quartzites, argillites, volcanic materials, and serpentines, with some limestone. The 



thickness of these beds, or of a part of them, was roughly estimated in two places as between 

 4,000 and 5,000 feet. Minimum total thickness say 4,500 



9,500 



Thus, the entire volume of the rocks of the Cache Creek formation as this is now defined, 

 may be assumed to be about 10,000 feet as a minimum, while I am inclined to believe that it 

 really exceeds 15,000 feet. 



A few characteristic fossils have been obtained in a number of places beyond the limits of the 

 present map. At Stuart Lake (latitude 54° 30'), Dease River (latitude 59° 15'), Frances River 

 (latitude 60° 30'), and on Tagish Lake (latitude 60°), fusuline limestones have been observed. 



To the westward of the Coast Ranges (in which it is probable that numerous iafolds of 

 Paleozoic rocks will yet be found) a formation known from its fossils to be of Carboniferous age 

 is agaia well represented. This has, so far, not been very minutely examined or reported in 

 detail, but it is known to comprise thick beds of limestones, argillites, and volcanic materials, 

 the latter being even more characteristic and in greater development than in the region here 

 specially dealt with. 



In the Rocky Mountains proper, or eastern member of the Cordilleran system, the section 

 which must now be regarded as the typical one for these latitudes is that worked out by Mr. 

 R. G. McConnell. In this section the Carboniferous period is represented by the Banff hme 

 series, which, including two shaly zones, has a thickness of 5,100 feet. This has jdelded a number 

 of fossils and these show that the series as a whole represents the lower part of the Carboniferous, 

 passing below into the Devono-Carboniferous. The later part of the Carboniferous period seems 

 either to be unrepresented, or, if represented at all, to find but a partial equivalent in the upper 

 shales. It is thus very probable that before the close of the Carboniferous the present position 

 of the Rocky Mountains formed part of a land area. 



It has already been noted that the lower portions of the Cache Creek formation may be 

 older than the Carboniferous period. The very general blending of the Carboniferous and 

 Devonian systems in the West shows that no well-marked line need be anticipated at the base 

 of the Carboniferous. The separation of any beds of Devonian age can only be made in the 

 event of the future discovery of characteristic fossils. The same may be said respecting the 

 possible existence of Silurian or Cambro-Silurian beds. 



Reference is made to the occurrence of limestone of the Cache Creek group 

 on Atlin Lake, British Columbia, where it is present on both sides of Taku Arm,^*^* 

 in latitude 59° 30'; and 10° farther south dolomites, argillites, serpentine, and 



