424 C. K. LE1TH 



II. Banded Argillite Division. 



(a) Greenish-gray slates, becoming bluish or light gray, and passing 



upwards into 

 (d) Purple slates, marked in the lower beds by pale, yellowish-green 

 seams, with faint bedding lines, which are wanting in the higher 

 beds. 

 (c) Bluish-gray and gray slates, often with cloudings of green, purple, 

 lilac, buff, or yellow, in places exhibiting a conspicuous banding 

 or ribboning of the beds. 

 III. Black Slate Division. 



Black, with some blue or gray slates, often studded with cubes of 

 pyrites, and very rusty-weathering. 

 Comment — Here again the Cambrian has been extended downward to 

 cover rocks, devoid of fossils, which have been mapped as Algonkian by 

 Van Hise. J 



Dawson 2 presents a brief note on Cryptozoon and Archseozoon 

 found in the pre-Cambrian. A general discussion is given of the 

 biological affinities of the Cryptozoon and Archseozoon, and descrip- 

 tions are quoted of younger forms which may be the successors of the 

 pre-Cambrian forms. 



Dawson, 3 in an account of the physical geography and geology of 

 Canada, sketches the distribution and characters of the pre Cambrian 

 rocks. 



Dawson 4 gives a general account of the pre-Cambrian rocks of 

 Canada. This is largely a discussion of pre-Cambrian classification 

 and nomenclature, based on a review of early and recent work on the 

 pre-Cambrian of Canada, and will, therefore, not be fully summarized. 

 A few of the more important conclusions may, however, be mentioned. 

 The Laurentian still includes both Fundamental Gneiss and the 

 Grenville series. 



1 Bulletin 86, U. S. Geol. Survey, PL V. Sixteenth Ann. Rep.t., PI. CVIII. 



2 Note on Cryptozoon and other ancient fossils, by Sir William Dawson: 

 Canadian Record of Sci., Vol. Ill, pp. 203-219. 



3 The physical geography and geology of Canada, by G. M. Dawson: Hand- 

 book of Canada, issued by the Publishing Committee of the Local Executive of the 

 British Assoc, Toronto, 1897. "~\ 



This is largely a general summary of the present state of knowledge concerning 

 the geology of Canada, and will therefore not be fully reviewed. 



4 Presidential address to the geological section of the British Association for the 

 Advancement of Science, by G. M. Dawson : Proc. Brit. Assoc. Adv. Science for 

 1897, Section C, p. 13 



