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INTRODUCTION. 
SCOPE OF EXCURSION. 
This excursion has for its objective an occurrence of 
Eozoon canadense and certain deposits of apatite, graphite 
and mica which lie within the southern edge of the Pre- 
Cambrian region immediately north of the Ottawa river. 
These deposits, while of minor economic importance and 
supporting only small and precarious industries, are never- 
theless of considerable geological interest. Leaving Mont- 
real by rail the excursion will follow the north shore of the 
Ottawa river to Ottawa, short northward trips being made 
from Papineauville to the Eozoon locality at Céte St. 
Pierre, from Buckingham to the apatite deposit at the 
Emerald mine and the graphite deposits at the Walker 
and Dominion mines, and finally from Ottawa to the 
Nellis mica mine at Cantley. 
GENERAL GEOLOGICAL DESCRIPTION. 
The geology of the region to be traversed admits of 
a clearly marked three-fold subdivision: 
3. Pleistocene and Post-Pleistocene. 
€, Saxicava sandr 
b. Leda clay. 
a. Boulder clay. 
2. Ordovician. 
Wittica- 
. Trenton. 
. Black River. 
. Chazy. 
. Calciferous. 
. Potsdam. 
I. Pre-Cambrian. 
c. Anorthosites. 
b. Ottawa gneiss (granite, diorite, gabbro.). 
= 
oOo Oo 
Pre-Cambrian. The oldest Pre-Cambrian rocks in the 
region to be visited are a series of highly metamorphosed 
sedimentary materials, probably the oldest rocks in eastern 
North America, to which the name Grenville series was first 
applied in this region [19]. These are intruded by immense 
bodies of granite, diorite and gabbro, collectively known 
