THE COBALT SERIES; ITS CHARACTER AND ORIGIN 125 
SECTIONS OF THE COBALT SERIES IN THE TIMISKAMING REGION, 
ONT., AND QUE.—Continued 
Rock Thickness Locality Reference 
PATEK OSCAR ee laren ots 220 “| North end Lake M. E. Wilson, zbid. 
Conglomerate....... Sona Opasatika, Pon- 
tiac Co., Que. 
SIIKOSC Heys. as ees 250 “ | Swinging Hills, M. E. Wilson, ibid. 
ip) = Te eerie ater BOSe a) enontiac Co, Oue: 
Conglomerate....... 70+" 
Conglomerate....... 65 “ | Labyrinthe Hills M. E. Wilson, zbid. 
PATIOS Rinna tens oie tays 4 TOS: Pontiac Co., Que. 
2 Reece ae eae nye 
Basal conglomerate-—Wherever the Cobalt series is seen in 
contact with the rocks of the older complex, the basal member 
of the series is usually a conglomerate. The outstanding feature 
of this basal conglomerate is its heterogeneity, not only in the size 
and angularity of the included fragments, but in the variability 
of the rock, both in texture and composition from point to point. 
In some places it is largely composed of coarse fragmental material 
with little matrix and, in other places, consists largely of matrix 
with few fragments. As a rule it is unstratified, but locally a 
partial alignment of the pebbles can be seen. 
The matrix of the conglomerate varies greatly in texture and 
composition and may be either coarse and feldspathic or exceedingly 
fine grained and slate-like in appearance; the coarser types are, 
however, by far the most common. Examined under the micro- 
scope the matrix is seen to be composed of angular, subangular, 
and round fragments of quartz, feldspar, quartz porphyry, mica 
schist, rhyolite, andesite, basalt, and other rocks inclosed in a 
cement consisting chiefly of chlorite, but usually accompanied by 
small quantities of carbonate, epidote and pyrite (Figs. 1 and 2). 
The pebbles and bowlders of the conglomerate include, even in 
a single rock exposure, nearly every variety of rock occurring in 
the older complex. Fragments of granite occur everywhere, and 
are commonly many miles from the nearest occurrence of this rock 
in the underlying basement from which the Cobalt series was 
evidently derived. As is generally characteristic of coarsely 
