1 64 REVIEWS 



vertical dip within tlie so-called Original Huronian, and others have been observed by 

 myself. These seem to occur around the outer portion of the Huronian basin, and 

 more gentle dips obtain in the central part. Evidently the Huronian has been sub- 

 jected to forces which the later Animikie has escaped. 



4. Assuming that the large areas of eruptive granite-geisses in the Lake Superior 

 region are of the same age, we find that the Upper Huronian has in many cases been 

 pierced by them, but that the Animikie always overlies them. 



A. P. Coleman. " The Huronian Question." American Geologist, Vol. 



XXIX (1902), pp. 325-34. 



Coleman discusses the Huronian question, his argument being mainly against the 

 correlation of the Animikie series of the Lake Superior region with the Upper 

 Huronian series. Evidence that the Animikie is unconformable above his Upper 

 Huronian series is summarized, and emphasis is placed on the points that both the 

 Upper Huronian and the Lower Huronian differ lithologically from the Animikie ; 

 they are metamorphosed and schistose as compared with the Animikie ; and they are 

 much folded aad highly tilted, in marked contrast to the Animikie. 



Comment. — For the most part the terms "Upper Huronian" and "Lower 

 Huronian," as applied by Professors Willmott and Coleman to rocks outside of the 

 part of the Original Huronian area of Logan on the north shore of Lake Huron, are 

 to be correlated respectively with the "Archaean " and " Lower Huronian " of the 

 United States geologists, and thus Van Hise's "Upper Huronian" or "Animikie" 

 comes above their " Upper Huronian." For such areas, therefore, there is no marked 

 difference of opinion as to the number and succession of series, but only difference in 

 names. However, when it comes to the correlations of these series with the rocks of 

 the Huronian series on the north shore of Lake Huron the difference is fundamental. 

 Coleman and Willmott, in common with other Canadian geologists, apply the term 

 " Upper Huronian" to the entire series north of Lake Huron mapped as "Huronian" 

 by Logan, and apply the term " Lower Huronian " to underlying greenstones, green 

 schists, and jaspers (as typically developed in the Michipicoten district). This Lower 

 Huronian series, with the addition of certain " Laurentian " granites, corresponds 

 approximately to what Van Hise, following the terminology of the U. S. Geological 

 Survey, has called the "Archaean" in this and other parts of the Lake Superior region. 

 But the sediments which Logan mapped as " Huronian," and which are classed as 

 "Upper Huronian " by Willmott and Coleman, have been divided on the north shore 

 of Lake Huron by Van Hise and Pumpelly, following Alexander Winchell, into the 

 "Lower Huronian" and "Upper Huronian" series, the break being placed at the 

 base of the Upper slate conglomerate. It is with these divisions of the Original 

 Huronian series that the correlation of the Upper Huronian and the Lower Huronian 

 series of the rest of the Lake Superior region has been made by Van Hise. Field 

 work done on the north shore of Lake Huron during 1902 by Professors Van Hise, 

 Seaman, and the writer presents further evidence of the correctness of this correla- 

 tion. A full discussion of the evidence is not possible here, but it will be presented 

 shortly in a general monograph on Lake Superior geology now in preparation. 

 Andrew C. Lawson. "The Eparchean Interval: A Criticism of the Use 

 of the Term Algonkian." Bulletin of the Department of Geology, Uni- 

 versity of California, Vol. Ill, pp. 61-52. 



Lawson criticises the use of the term "Algonkian." He emphasizes the impor 

 tance of the interval, which he calls the Eparchsean interval, between the " Huronian ' 



