4 
MUSEUM BULLETIN NO. 22. 
The Pre-Cambrian succession north of Lake Huron follows: 
Table of Formations. 
Diabase sills and 
dykes, etc. 
Huronian 
Cobalt series 
Bruce series 
Pre- 
Huronian. 
White quartzite, yellow chert, and 
limestone 
Banded cherty quartzite 
Lorrain quartzite: red quartzite, 
jasper, conglomerate, and white 
quartzite 
Gowganda formation l : boulder con- 
glomerate, greywacke, laminated 
greywacke, quartzite, and im- 
pure limestone 
Unconformity. 
Serpent quartzite: white quartzite 
Espanola limestone: siliceous mag- 
nesian limestone, less pure than 
the Bruce limestone 
Espanola greywacke: calcareous, 
thinly bedded greywacke 
Bruce limestone : siliceous banded 
limestone 
Bruce conglomerate: boulder con- 
glomerate 
Mississagi quartzite; quartzite and 
arkose, conglomeratic at base 
and resting upon a decomposed 
pre-Huronian surface 
Unconformity. 
Granite-gneiss batholithic in- 
trust ves 
Igneous meta-schists and meta- 
sediments 
Feet 
700 
5500-6000 
3000 + 
1100 
0-75 
350 
150-200 
20-150 
1000-2000 
The argument developed hereafter is essentially simple. 
The granite at Killarney is shown to bear a certain relationship 
to sediments which are regarded as Huronian in age and from 
this relationship the age of the granite is determined. If doubt 
existed regarding the age of the sediments, equal doubt would 
fall upon the age ascribed to the granite. It is necessary, there- 
fore, to establish conclusively the identity of the Huronian 
1 This name is suggested in a Geological Survey Memoir, "The Geology 
of Onaping Map-area, ' now in preparation. 
