SUMMARIES OF PRE-CAMBRIAN LITERATURE OF 



NORTH AMERICA FOR 1909, 1910, 1911, AND 



PART OF 191 2 







EDWARD STEIDTMANN 







University of Wisconsin 





CONTENTS 



I. 



General 

 1909 

 1910 

 1911 





II. 



Eastern Part of North America 



III. 



Lake Superior Reg 

 sissippi Valley 



ion and Isolated pre-Cambrian Areas of the Mis- 



IV. 



Ontario, Northwest Territories, and East Coast of Hudson Bay 



V. 



Quebec 



^ 



VI. 



The Cordilleras 



I. GENERAL 



1909 



Adams^ maintains that the pre-Cambrian may be divided on 

 the basis of major diastrophic movements into Eo, Meso, and 

 Neo-Proterozoic, and that this basis may serve the purpose of inter- 

 national correlation better than comparative study of unconformi- 

 ties. He objects to the two fold classification of the pre-Cambrian 

 suggested by Van Hise, on the ground that the break at the base of 

 the Animikie is as great as that which follows the Keewatin. 



Adams^ states that amphibolites consisting of aggregates of 

 hornblende, pyroxene, mica, and other minerals, in various propor- 

 tions, have developed from {a) the metamorphism and recrystalHza- 

 tion of impure calcareous sediments; (b) alteration of certain basic 

 dikes; and (c) alteration of limestones by bathoHthic intrusions of 

 granite. The granites show marginal digestion of limestones 



^ F. D. Adams, "The Basis of pre-Cambrian Correlation," Jour. GeoL, XVII, 

 No. 2 (1909), 105-23. 



^ F. D. Adams, "Origin of Amphibolites of the Laurentian Area of Canada," Jour, 

 GeoL, XVII, No. i (1909), 1-18. 



