No. 2.] MACFARLANE — CANADIAN STRATIGRAPHY. 97 



•' same series of rocks in the Province of Quebec occupies a belt 

 " along the west side of the Quebec group, having a breadth of 

 " about twenty miles, and including all undoubted sedimentary 

 " and fossiliferous strata. It is the same band of rocks which 

 '' continuins: southward into Vermont has there beun called the 

 '• Taconic, and which Dr. Hunt wishes to classify as Upper Cam- 

 " brinn. We have already seen that the term Cambrian is much 

 " more applicable to the Green Mountain series, and there would 

 " appLiar to be no good reason for ceasing to regard these rocks 

 "as belonging to the Silurian system. As has already beeu'ex- 

 " plained, however, it would be proper to exclude from that 

 " series any non-fossiliferous rocks whose aspect is semi-crystal- 

 '•' line, and which have been so frequently classed as metamorphic 

 " Lower Silurian, These, as we have seen, it is much more 

 *' rea!^onable to class with the Cambrian rocks." (pp. 15 and 16.) 

 From these quotations it will be perfectly evident that Mr. 

 Selwyn's views as to the age and structure of the Quebec group 

 are the same as those I have held for the last seventeen years 

 and repeatedly brought before the public. It may seem a matter 

 of little consequence as to where the merit of priority lies, but I 

 confess I think differently, and maintain that Mr, Selwyn's recent 

 paper ought to have contained some allusion to the passages 

 above quoted. 



But, in spite of all this, I feel bound to say that the matter is 

 not ended here ; that the independent student of our geology 

 will neither accept Mr. Selwyn's views nor any others, unless they 

 satisfactorily dispose of the difficulties which have all along beset 

 this subject. Mr. Selwyn banishes Potsdam strata from the 

 proximity of the Levis rocks, and claims that his new divisions 

 have " at least the advantage of simplicity," This may readily 

 be admitted for what it is worth, but they do not in the slightest 

 degree meet the question with which Sir W, E, Logan found 

 himself face to face during the latter part of his lifetime, and 

 which may thus be stated: How can this Levis formation be 

 really Lower Silurian in age when it underlies, unconformably, 

 the lowest of Lower Silurian rocks, namely, the typical Potsdam- 

 sandstone of the St. Lawrence valley ? Mr. Selwyn says, that 

 the Levis formation is Lower Silurian, and the horizontal Pots- 

 dam sandstone is Lower Silurian too, and thinks that he has 

 effectually disposed of the question '• without invoking any of 

 " the numerous almost impossibilities in physical and dynamical 

 Vol. IX. G So. 



