PRE-CAMBRIAN NOMENCLATURE 



A. P. COLEMAN 

 University of Toronto 



The report of the committee of American and Canadian geologists 

 appointed by the surveys of the two countries to compare notes in the 

 field and decide upon a suitable nomenclature for the pre- Cambrian 

 formations of the Upper Lakes, forms an important landmark in the 

 geology of that region. While it is evident from the report itself that 

 the results attained represent a compromise, not perhaps altogether 

 satisfactory to either party, in the long controversy which has been 

 waged over the relationship of these complex and difficult formations, 

 yet it is to be hoped that, at least in its broad lines, the proposed 

 nomenclature will be accepted by future workers in the region, putting 

 an end to the confusion which has reigned. The position and reputa- 

 tion of the members of the committee give their decisions great weight, 

 and doubtless their nomenclature is the best that could be framed to 

 reconcile the two points of view. 



Accepting it as such it may still not be amiss to discuss certain fea- 

 tures of the report, as they appear to one who has worked over much 

 of the region on the Canadian side. 



The brief summing up of the results of their field-work in the vari- 

 ous districts visited is of use as showing the ground covered by the 

 committee, and the materials which they brought to bear on the solu- 

 tion of the problems of the pre- Cambrian; and in general their con- 

 clusions seem quite justified, in spite of the short time which could be 

 devoted to any one place. Several members of the committee had of 

 course previously done a large amount of work in the critical localities 

 and were thoroughly familiar with the field relationships. It is to be 

 regretted, however, that so few of the characteristic sections of the 

 Rainy Lake region were visited, and that the important Michipicoten 

 district was not visited at all. In the latter case Professors Van Hise 

 and Leith had, however, acquired some first-hand knowledge of the 

 field relations. 



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