COMMENT ON THE "REPORT OF THE SPECIAL COM- 

 MITTEE ON THE LAKE SUPERIOR REGION" 



ALFRED C. LANE 

 Lansing, Mich. 



In signing and assenting to the publication of the "Report of the 

 '.Special Committee on the Lake Superior Region/' 1 it was agreed 

 that the various members of the committee should have a right to add, 

 ■or to publish elsewhere, notes explanatory of their subscription to 

 .the official creed. It may perhaps be worth the cost for me to explain 

 why I was willing to accept "Laurentian" as a term apparently 

 stratigraphic and co-ordinate with stratigraphic terms, though the 

 formation is separated from the Keewatin (and Huronian?) by 

 ■eruptive rather than unconformable contact — a kind of contact that 

 J take not to have stratigraphic meaning. 



If I had believed that this committee or any committee could 

 make a final and binding determination of names, I should not have 

 signed it, for I think the scheme will probably not prove to be final; 

 but I did sign it as being the best practical working arrangement, 

 with our present knowledge. Words are but labels for concepts, and 

 •our concepts must vary more or less as our knowledge increases, 

 while it is desirable that our labels should remain as fixed as possible. 

 I hope that the decision of the committee will prove to be the best 

 that could have been done at present toward naming the rock forma- 

 tions so that future modifications will still apply the same names to 

 most of the rocks involved. In the first place, I may frankly say 

 that I have yet to see any rocks in the Laurentian, as defined by the 

 committee, that I should class as a softened underlying formation. 

 The granite and gneisses, etc., are crystallized from aqueo-igneous 

 fusion, and have been at a temperature (under conditions) consider- 

 ably beyond the consolidation point, as it seems to me, 2 as their grain 

 shows. 



1 Journal of Geology, Vol. XIII, pp. 89—104. 

 -2 American Geologist, February, 1905. 



457 



