140 ROYAL SOCIETY OF CANADA 
who have studied the region since Lawson’s luminous reports on it, 
and may be looked on as satisfactorily proved. Were the upper 
Huronian sediments also laid down before the upheavals of the Lau- 
rentian and the folding of the Keewatin ? 
This question has been differently answered by different geolo- 
gists. Logan and Murray assumed that the Huronian rested uncon- 
formably on the Laurentian, but described no section where this is 
proved. Irving and Van Hise concluded that they had found such 
a section on some small islands east of Thessalon, but Barlow, after 
studying the same section, believed the contact eruptive. Willmott 
and myself have twice visited the locality with a view to settling the 
matter, but do not feel absolutely sure of the relationship, though 
inclining to the belief that the contact is eruptive. 
In our last visit, at a time of low water, in the spring of 1900, 
we noted on one of the islands a conglomerate crowded with boulders 
overlying a laminated quartzite with a few boulders of granite or 
gneiss looking like the Laurentian in its lower part; which apparently 
rested on the Laurentian. On a point of the mainland not far off 
is an auto-breccia of granite and gneiss somewhat suggesting a basal 
conglomerate. On an islet to the south of this, however, where 
conglomerate and granite come together, the latter appears to have 
fused and inclosed parts of the conglomerate in an eruptive way. The 
evidence seems too uncertain to decide the matter positively. 
The only other example that has been described of a basal upper 
Huronian conglomerate resting apparently in place on the Laurentian, 
is from Baie des Péres, on the Quebec side of Lake Temiscaming, 
where Barlow and Ferrier found a mass of granite passing through 
a weathered brecciated zone up into a conglomerate forming the base 
of a series of greenish Huronian quartzitest This conglomerate 
is evidently upper Huronian, since it contains, like the Thessalon con- 
glomerates, some pebbles of jasper, evidently derived from the iron 
range, the top of the lower Huronian; and, as far as I am aware, it 
is the only example known of an undoubted Huronian conglomerate 
formed of underlying Laurentian materials. 
On the other hand, there are in various places examples of upper 
Huronian conglomerates having Laurentian rocks in eruptive contact 
with them, as Willmott and myself have shown at Michipicoton.? 
Sir William Logan believed that the Huronian schist conglomerate and 
the Laurentian at Doré river in this region were more or less blended,’ 

* On the Relations and Structures of certain Granites and Associated 
Arkoses, Rep. B.A.A.S., Toronto, 1897, pp. 656-660; also Barlow in Geol. Sur. 
Can., 1897, 195 I. 
? Bur. Mines, 1902, The Michipicoton Iron Region, 152-185. 
* Geol. Can., p. 54. 
