638 REPORT — 1897. 



system of the Palreozoic, but of late years the position has been taken by gjood 

 authorities that the true base of the Cambrian is to be found at the Olenellus 

 zone- ard while it appears very probable that, when fossils are found in the 

 Animikie, they mav be referable to this zone, the adoption of such an apparently 

 arbitrary line certainly, for the time, must be considered as placing the Cambrian 

 reference of the beds in question in doubt; but it does not interfere with a belief 

 that if they should be found to be lower than Cambrian as thus defined, they may 

 at least be considered as still in all probability Palfeozoic. 



The definition of the horizon of Olenellus as that of the base of the Cambrian 

 IS a question almost entirely palseontological, into which it is not proposed here 

 to enter further than to point out that it is only partially justified by what is 

 known of North American geology. In the Atlantic province, and in the 

 Appalachian region, there appears to be a very general physical break at about 

 this stage, which it seems likely may correspond with the great unconformity at 

 the base of the Animikie ; but in the Rocky Mountain or Cordilleran region the 

 Olenellus zone has been found high up in a series of conformable and similar sedi- 

 ments coincidino- with no break, and from these lower sediments some organic 

 forms have been already recovered, but not such as to indicate any great diversity 

 in fauna from that of the recognised Cambrian. Similarly, in one part of eastern 

 Canada, Matthew has lately described a fauna contained in what he names the 

 Etcheminian group, regarded by him as earlier than the Olenellus zone, but still 

 Palajozoic. Recent discoveries of a like kind have been made in other parts of 

 the world, as in the Salt Range of India. These facts have only last year been 

 particularly referred to by Mr. Marr in his address to the Section. 



The general tendency of our advance in knowledge appears, in fact, to be in the 

 direction of extending the range of the Palaeozoic downward, whether under the 

 old name Cambrian, or under some other name applied to a new system defined, 

 or likely to be defined, by a characteristic fauna ; and under Cambrian or such new 

 system," if it be admitted, it is altogether probable that the Animikie and Kewee- 

 nawan rocks must eventually be included. 



In other words, the somewhat arbitrary and artificial definition of the Olenellus 

 2one as the base of the Cambrian, seems to be not only not of world-wide appli- 

 cation but not even of general applicability to North America ; while, as a base 

 for the Palffiozoic ^on, it is of still more doubtful value. In the Cambrian period, 

 •as well as in much later geological times, the American continent does not admit of 

 treatment as a single province, but is to be regarded rather as a continental barrier 

 iDctween two great oceanic depressions, each more or less completely diflBrent and 

 self-contained in conditions and history — that of the Atlantic and that of the 

 Pacific. On the Atlantic side the Olenellus zone is a fairly well-marked base for 

 the Cambrian ; on that of the Pacific it is found naturally to succeed a great 

 consecutive and conformable series of sediments, of which the more ancient 

 fauna is now only beginning to be known. 



In thus rapidly tracing out what appears to me to be the leading thread of the 

 liistory of the pre-Cambrian rocks of Canada, and in endeavouring to indicate the 

 present condition of their classification, and to vindicate the substantial accuracy of 

 the successive steps taken in its elaboration, many names and alternative systems 

 of arrano-ement proposed at different times, by more or less competent authorities, 

 have been passed without mention. This has been done either because such 

 names and classifications appear now to be unnecessary or unfounded, or because 

 they relate to more or less local subdivisions of the ruling systems which it is not 

 possible to consider in so brief a review. This has been particularly the case in 

 regard to the much-disputed region to the south of Lake Superior, out of which, 

 Tiowever after some decades of complicated and warring nomenclature, a classi- 

 fication trending back substantially to that originally established and here 

 advocated, is being evolved (albeit under strange names) by the close and skilful 

 stratigraphical work in progress there. 



It has also been my object, in so far as possible, by omitting special reference 

 to divergent views, to avoid a controversial attitude, particularly in respect to 

 matters which are still in the arena of active discussion, and in regard to which 



