GENERAL CONCLUSIONS 699 



mately north-south in the western part of the continent, as advocated by 

 Euedemann. 



5. There is not sufficient warrant for a statement that North America 

 reacted as a "unit against the diastrophic forces active in pre-Cambrian 

 time/^ as advocated by Euedemann. On the contrary, because of notable 

 variations in structural trend, even in local portions of the continent 

 (see map), and because of the localization of orogenic forces, both in 

 space and time, during the very long post-Cambrian history of the conti- 

 nent, it is more reasonable to believe that similar localization obtained 

 during pre-Cambrian time. 



5. The absence of pre-Cambrian structural data from vast areas (fully 

 one-half) of North America causes a large element of uncertainty to 

 enter into any attempt to generalize with regard to the trend-lines of 

 pre-Cambrian folds and foliation. 



Discussion 



Dr. E. Euedemann sent the following letter, which was read in open- 

 ing the discussion : 



It is just as well that Professor Miller attracts attention to my paper on 

 the "Existence and Configuration of pre-Cambrian Continents" by attacking 

 its premises. This is always the surest means of keeping a new-born idea 

 from the limbo of the still-born and forgotten. 



The points which Professor Miller proposes to raise, according to the pro- 

 gram, refer to premises that had been recognized by me as the ones that 

 needed protection and that therefore have been frankly stated in the paper to 

 be open to discussion and the evidence for which has been fully presented, as 

 far as the limited space allowed. 



The first point is that the Archean basement complex in North America has 

 not everywhere undergone severe metamorphism. This is, as far as I can see, 

 of no critical importance for the solution of the problem involving the presence 

 and configuration of the pre-Cambrian continents and may, therefore, be 

 passed without comment. 



The second point is that the Archean basement complex has not been uni- 

 versally intensely folded. In this regard Professor Miller disagrees, as far as 

 the Adirondacks, his field of study and experience, is concerned, with all the 

 other geologists that have worked in the Adirondacks, and that fact is set 

 forth in my paper. As my conclusions must be based, of course, on the con- 

 sensus of authors and not on a single dissenting view, the latter, however 

 interesting, is of no account in this matter. 



The third point is that "the pre-Cambrian folding does not exhibit such 

 uniformity of direction as has been recently advocated" (by the writer). The 

 claim that the folding is uniform in its grand outlines is based on the evidence 

 gathered from the pre-Cambrian literature of the world there cited and will 

 have to stand or fall with the correctness of the many observations quoted. 



