INAPPLICABILITY OF THE TERM "ALGOXKIAN, 



173 



estimate of the thickness of the Cambrian arrived at in the Selkirks is, how- 

 ever, greater than that elsewhere known. 



In a late paper on the stratigraphical position of the Olenelhis fauna,* 

 Mr. C. D. Walcott has suo^wsted that the Bow River series of the Canadian 

 Rocky Mountains maybe regarded as "Algoukian." He does not, however, 

 appear to have been aware of the fact above alluded to, that the Olenellus 

 fauna characterizes both the upper part of this series and the lower part of 

 the Castle Mountain group. With this circumstance in evidence, together 

 with the apparently complete stratigraphical conformity of the two series, 

 the writer cannot but regard it as more in consonance with the conditions, so 

 far as these are known, and therefore as more philosophical to include, for 

 the present at least, the whole of this great conformable mass of rocks, tD its 

 base, under the name Cambrian. In Utah and Nevada, where Mr. Wal- 

 cott's observations on the western Cambrian have chiefly been made, it 

 seems that the beds classed as "Algonkian " likewise in general conform- 

 ably underlie those in which the Olenellus fauna is known, the conditions 

 being apparently in most cases similar to those here described. On the 

 propriety of the use of the new term in regions with which he is not person- 

 ally familiar the writer wishes to offer no opinion, but he may take the 

 opportunity of stating that he has met with no rocks in Canada to which its 

 application can at present be considered appropriate, either in the interest 

 of precision in the expression of facts already ascertained, or because of 

 the discovery of heretofore unrecognized relations as between the older 

 formations. 



So far as could be definitely ascertained in the course of the rather 

 hasty examination upon which this paper is based, the lowest beds of the 

 Cambrian in the Selkirks (seen not far east of Albert Cafion station) are 

 in angular conformity to the xlrchean rocks (seen to the west of the same 

 station). The actual junction, however, remains to be studied, as there is 

 here a gap in the section on the line of railway. In the meantime it may be 

 stated that, notwithstanding the appearance of conformity, there is reason to 

 believe that a great break in time is here passed over ; for, although coarse, 

 glittering micaceous schists are found in some parts of the Cambrian, the 

 rocks of the lower series differ markedly even from these in their completely 

 crystalline character. The essential diversity in age of the two series is fur- 

 ther shown by the circumstance that the highest rocks of the Archean here 

 met with do not include the notably silicious beds, the calcareous gneisses 

 and the marbles which characterize the upper parts of this system as ex- 

 posed on Kootanie lake and near Shuswap lake. It is also found that the 

 very numerous granitic veins which everywhere cut the Archean rocks do 

 not enter the overlying Cambrian strata, while a large quantity of pale-pur- 



* Am. Journ. ScL, 2ad sen, vol. XXX VIII, 1889, p. 32. 

 XXVI— Bull. Geol. Soc. Am,, Vol. 2, 1890. 



