GEOLOGICAL EXPLORATIONS AND LITERATURE. 19 



Proceeding along the inouutaiu ridges of the northern part of tlie range, between 

 the main stream and the outlet of Lac, des Anglais, we eneountei- other varieties of 

 rocks, feldspathie, granitic, and hornblendic iu their composition, apparently an 

 independent uplift (ir outburs't. Along this whole line, how^-ver, the metamorphic 

 rocks of the southern ridges of the range are continuous from near the Montreal to 

 lac des Anglais. They have, at different times, been pushed over the granites at the 

 south, distorted, broken, aud tilted up in different degrees, but always in the sauu- 

 direction. The nortlieru piu-tion of the range exhibits to my miud evidence of /oh/- 

 periods of igneous actiou, producing /oh/- formations of locks of a trappose cast, which 

 I have represented separately on the map. 



They are: 1st, black and red trap; I'd, greenstone trap, embracing or gradu- 

 ating into massive hornblende and syenite at the west; od, augite and horiibleiide 

 rocks in mass, also embraciug granite and syenite; 4th, granite, syenite, and coarse 

 hornblende rocks, uorth of Lac des Anglais. 



But how' to decide the order or relative age of these protrusions f It appears 

 that the same materials under ditt'eieut circumstances of tluidity, pressure, and 

 rapidity of cooling may take all these forms. 



At present I can only place these four varieties iu one (jroupj filling a geological 

 epoch of no great duration, and place it between the era of the led sandstone depos- 

 its and the inetaiiiorjihic uplifts; for it is by the ai)peuiance of this group that both 

 those systems have been pushed aside, one to the north, the other to tlie south. 

 Whether the schistose rocks, before their upheaval aud metamorphosis, were older 

 or newer than the sairdstone 1 do not decide; but both the schists and the unaltered 

 sedimentary rocks are more ancient thau the above group numbered from one to four 

 (pp. 429-43tl). 



The g-eolog-ical map mentioned in tlie above quotation was never 

 printed; btit its mniii features were embodiccl in Owen's general geologi- 

 cal ma}) of the northwest.' PI. iv is a reproduction, save as to the omis- 

 sion of colors, of the original. In a similar manner Whittlesey's fota- cross- 

 sections of the Bad river country are reproduced in PI. iii. 



In Whittlesey's classitication of the formations of the l>ad river 

 country, aliove given, the red sandstone (Iff) includes horizontal sandstones 

 belonging, as our belief is, to the Potsdam sandstone, and also \ertically 

 placed sandstones belonging to the Keweenaw or Copper series. To the 

 latter series belong Whittlese^•'s foi-mations from 16 to 2//, inclusive. His 

 group of metamorphosed rocks (3) is aboitt equivalent to the iron-bearing 

 series which forms the subject of the pre.sent volume. His group of granitic 



' See volume of illustrations accompanying; the Report, 



