REVIEWS 165 



and Animikie series, that is, between the Lower Huronian and Upper Huronian, of 

 the United Stales Geological Survey, and argues that no one term such as " Algon- 

 kian" should include a break of this importance. It is proposed to restrict "Algon 

 kian " to the Animikie and Keweenawan rocks, and to retain Dana's term "ArChsean"- 

 for all rocks below the Animikie, i.e., below the Eparchasan interval, and also to retain 

 the terms " Laurentian " and " Huronian," as subdivisions of the Archaean, with the 

 significance originally given them by Logan. The correlations of the Animikie with 

 the Keewatin of Minnesota and with the Upper Huronian of Lake Huron is regarded 

 as an error, because of dissimilarity in lithology, stratigraphy, and in relations to 

 intrusives. Following Willmott and others, it is believed that the Animikie is younger 

 than the (Upper) Huronian series of Lake Huron, and thus later than the Eparchaean 

 interval. Emphasis is placed on the marked lithological similarity in the sedimentary 

 series below the Eparchsean break in the Lake Superior and Lake Huron region, and 

 the probable correlation of these rocks with the Original Huronian series. Summar- 

 ized in tabular form, the correlation proposed is as follows : 



j Cambrian (Upper division or Potsdam only). 

 Unconformity. 

 Paleozoic, -j f Keweenawan. 



I Algonkian. -J Unconformity. 



I, t Animikie = Penokee = Upper Marquette. 



Eparchsean Interval. 



Huronian =Upper Keewatin =Lower Marquette, etc. 

 I Unconformity. 



Laurentian, so called, granite gneisses, etc, (intrusive in the Ontarlan) and the 

 J Carlton anorthosites, 



f Keewatin = Lower Huronian = Crystalline schists of south shore 



Ontarian 



invaded by granite gneisses. 



I Unconformity. 

 I Coutchiching. 



Comment. — Concerning the correlation of the Animikie with the Upper Huron- 

 ian the comment on Professors Willmott and Coleman's articles, summarized on a 

 preceding page, is pertinent. Dr. Lawson implies that the Animikie has been corre- 

 lated by the U. S. Geological Survey with the entire sedimentary Huronian series of 

 the north shore of Lake Huron, while it has been correlated only with the portion of 

 this series above the limestone ; and against such a correlation his argument loses 

 some of its force. If the Keweenawan and Animikie series are not Cambrian, as 

 they are held to be by Lawson, but are pre-Cambrian, as held by the U. S. Geological 

 Survey, then Lawson's objection to the term "Algonkian," as replacing in part the 

 old term " Archaean," would prevent its application even to the Animikie and 

 Keweenawan rocks to which he restricts it. As already noted, the nomenclature of 

 Lake Superior and Lake Huron series is being fully discussed in a general monograph 

 on Lake Superior geology now in preparation. Arguments for the adoption and 

 retention of the term "Algonkian " will be summarized, together with new arguments 

 developed in recent field work. 



C. R. Van Hise. " Geological Work in the Lake Superior Region." P7-o- 



ceedings of the Lake Superior Mining Institute, Vol. VII (1902), pp. 62-69. 



Van Hise briefly sketches the history of geological mapping in the Lake Superior 



region, calling attention to the difficulty of preparing accurate maps, and concludes that 



the maps which have been published from time to time since the earliest map of Foster 



