908 REVIEWS 



Province of Quebec, and the associated gneisses resemble the 

 Fundamental Gneiss of the same region. The greatest thick- 

 ness of the Shuswap rocks so far measured, where there is no 

 suspicion of repetition, on Kootenay Lake, is about 5,000 feet, 

 but even here there are doubtless included considerable inter- 

 calations of foliated eruptives. 



Schrader 1 describes certain granites and schists seen in a 

 reconnaissance along the Chandler and Koyukuk rivers of Alaska. 

 These are referred to as " basal " and certain of the schists are 

 correlated with Spurr's Birch Lake series of schists, but no 

 attempt at further correlation is made. 



Brooks 2 describes the Archean of the Tanana-Yukon divide. 

 A broad belt of crystalline rocks extends in a northeast-south- 

 west direction in the region of the Tanana-Yukon divide, 

 embracing a series of gneisses, mica-schists, basic schists, and 

 various intrusives, chiefly of an acid character. Near the middle 

 Tanana this series bends to the west and south, and its continua- 

 tion is to be sought for in the region of the upper Kuskokwim. 

 To the southeast this belt is probably continued by the granitic 

 rocks on the Pelly River, described by Dawson. What evidence 

 we have goes to show that this is the basal series of the Yukon 

 Basin, and as it contains no recognizable detrital material it can 

 properly be assigned to the Archean. Whatever the original 

 character of the rocks may have been, they are now essentially 

 mica-schists and gneisses, with considerable intrusive material. 

 Their metamorphic condition is the strongest argument for con- 

 sidering them older than any of the sedimentary rocks. 



Comstock 3 reviews the stratigraphy of Arizona. Granites, 

 gneisses, and schists, probably of pre-Cambrian age, occur at 



*" Preliminary Report on a Reconnaissance along the Chandler and Koyukuk 

 Rivers, Alaska, in 1899," by F. C. Schrader, Twenty-first Ann. Rept. U. S. Geol. 

 Surv., Part II, 1901, pp. 441-86; with sketch map. 



2 "A Reconnaissance from Pyramid Harbor to Eagle City, Alaska, Including a 

 Description of the Copper Deposits of the Upper White and Tanana Rivers," by 

 A. H. Brooks, Twenty-first Ann. Rept. U. S. Geol. Surv., Part II, 1901, pp. 331- 

 91 ; with sketch map. 



3 "The Geology and Vein Phenomena of Arizona," by T. B. Comstock, Trans. 

 Am. Inst. Min. Eng., Vol. XXX, 1900, pp. 1038-1101. 



