320 Selwyn — Geological Age of the Saganaga Syenite. 



accompanied by Keewatin schists is therefore quite probable 

 and that it is of Huronian not Laurentian age has always been 

 supposed by Canadian geologists who have examined it. I am 

 gratified to learn that this fact is now apparently recognized by 

 Mr. H. Y. Winchell. 



A few remarks on the use of the names Huronian, Coutch- 

 iching and Keewatin are I think called for in view of the very 

 erroneous ideas that have been promulgated, and of which the 

 paper now referred to is an instance, respecting the Huronian 

 system in Canada and the attempt to subordinate it to new and 

 comparatively unknown names or to confound it and associate 

 it with Paleozoic formations with which it has nothing in com- 

 mon. It is even indicated as Huronian on the map of .1866, 

 though then the extent of it as also of many other similar 

 areas had not been ascertained. 



The name Keewatin as well as Coutchiching was originated 

 on this Survey by Dr. Lawson. I sanctioned the use of these 

 names in the Survey publications, but only as being useful to 

 designate subdivisions, more or less local, of the great series of 

 Archaean rocks, which is widely distributed in Canada, at inter- 

 vals from Belle Isle Strait and Labrador to Lake Winnipeg, 

 and thence perhaps to the Arctic Ocean and which has always 

 been known and described wherever it has been recognized in 

 Canada, as Huronian or Upper Archsean. The name Huronian 

 is not, and never was used in Canada as equivalent to Taconic. 

 The latter term, so far as I can make out, like Quebec Group, 

 as depicted on the published maps, included parts of all 

 the formations from Huronian up to Hudson River shales 

 inclusive. Huronian, on the other hand, was always sup- 

 posed to occupy in Canada one and the same interval 

 in geological time, viz : that antedating the lowest Pale- 

 ozoic. It was never supposed, like Taconic, to include 

 Paleozoic formations though areas of it had in error been 

 included in them. The Keewatin area of the Lake of the 

 Woods had always been recognized as Huronian and the 

 Keewatin schists are simply one lithological subdivision of 

 that wide spread system. Perfectly similar schists occur in 

 some portion of all the Huronian areas shown on the Geolog- 

 ical map of Canada, 1882, and everywhere the system presents 

 similar characters, mineral, lithological and physical, and, as I 

 said of these rocks in 1879, they are largely of volcanic and 

 igneous origin. Clastic, pyroclastic or aqueo-igneous and mas- 

 sive igneous rocks are intimately associated and interbedded 

 and all have been subjected to such intense and long continued 

 dynamic and thermochemic metamorphism as often to have 

 obliterated their original characters. Microscopic investigation 

 is now proving the correctness of this somewhat old strati- 



