376 DR. J. W. DAWSON ON THE GEOLOGY OF THE 
28. OznsERVATIONS on the Guonoey of the Line of the CANADIAN 
Pacrric Ratnway. By J. W. Dawson, LL.D., F.RBS., F.G.S., &e. 
(Read April 23, 1884.) 
Havine had an opportunity last summer of passing over the line of 
this railway, and of examining some of the sections exposed on the 
road and in its vicinity, it may be useful to note the facts observed. 
All of the country on both sides of the line has been more or less 
explored by the officers of the Geological Survey, more especially by 
Dr. Selwyn, Dr. G. M. Dawson, and Dr. R. Bell; and without 
repeating what they have published, 1 shall confine my remarks 
chiefly to facts discovered or brought into greater prominence in the 
construction of the road. 
Between Ottawa and Port Arthur the road was only partially 
opened last summer, though it had penetrated into the region of © 
typical Huronian rocks north of Georgian Bay. Next summer it 
will be opened throughout, or at least to Algoma Mills, whence 
steamers will run on Lake Superior to Port Arthur. This 
section of the road will be of great geological interest, as it 
abounds in cuttings through Laurentian and Huronian rocks, and 
will also expose the Kewenian or Upper Copper-bearing series and 
other formations which, though newer than the Huronian, are 
believed to be Pre-Cambrian. Last summer, travellers were con- 
veyed by steamer from Collingwood to Port Arthur, through Lakes 
Huron and Superior, and it was at Port Arthur that their geo- 
logical experiences began. 
Port Arthur is at the head of Thunder Bay, and opposite it are 
the grand trappean masses of Thunder Cape and of the islands in 
front of it—masses which are associated with the Kewenian series. 
Near the town of Port Arthur the rocks exposed are dark- 
coloured quartzites and quartzose slates, having occasional veins of 
white quartz and of amethyst. These beds are believed to underlie 
the Kewenian series, but to be newer than the true Huronian *. 
Their surfaces show a few peculiar markings, which may be af 
organic origin, but are not determinable. 
From Port Arthur to Rat Portage the country is at first low, 
with many swamps and ponds; but occasional rock-cuttings show 
different varieties of Laurentian gneiss and bands of greenish schis- 
tose beds, probably Huronian. In the latter occur the veins now 
being worked for gold in this vicinity. I did not visit any of the 
mines; but I saw specimens, more especially from the ‘‘ Huronian 
Mine,” about 70 miles from Port Arthur. They consisted of white 
quartz holding visible gold and sylvanite in a rock which appeared 
to be chloritic slate. Several of these veins are now being worked 
on the shore of the Lake of the Woods, and are very accessible from 
Rat Portage. In approaching the place last named, fine sections 
* Animiké series of Hunt. 
