The Michipicotcn Hitroniaii Area. — Wilhnott. 15 
tion, north of Goetz lake, east of Manitovvick, and elsewhere. 
Commoner occurrences are the various green schists, chlorite, 
hornblende, mica and sericite schists. Presumably all these 
schists are derived from lavas, basic and acidic. The dip of 
the schists is always nearly vertical and the strike follows close- 
ly the line of contact with the g"ranite to be described later. 
Succeeding" these schists, perhaps interbedded with them, 
are the earliest sediments of the region. The most character- 
istic of these is a belt of ferruginous chert, which has been 
found at intervals for about sixty miles. This rock consists 
of banded hematite and silica with usually some residual car- 
bonate of iron. The bands vary from one-tenth of an inch in 
thickness up to several inches. The silica is sometimes very 
like loaf-sugar ; again it is like quartzyte, a chert, or a jasper. 
Red jasper is, however, not infrequent. The hill at the back 
of the Helen mine is a huge mass of siliceous carbonates. The 
rocks as a whole, and the mode of occurrence of the ore, are 
strikingly like the Lower Huronian iron formations of Mar- 
quette and Tower. 
Besides the iron formation, beds of carbonaceous shales 
and limestones have been recognized at several points. Shale 
occurs interstratified with the ferruginous chert at Iron lake. 
Near Paint creek and at Eleanor lake it has also been foimd. 
Whether it always underlies the iron formation is undeter- 
mined, but it probably does not. The cherty limestone has 
been traced in a fairly continuous line from the Helen mine to 
the east of Parks lake, a distance of twelve miles. 
Overlying these sediments is a very persistent belt of schist 
conglomerate. It is well exposed at the mouth of the Dore, 
where it was studied by Sir William Logan and described bv 
him in the Geology of Canada*. Colemanf describes 
the boulders as "granites most frequently, then quartzvtes or 
sandstones with pebbles generally small, next green schists, 
then felsyte schists and porphyroids, and finally a few gneisses, 
but none of the Laurentian type." .V thin section of one of the 
f|uartz\-te pebbles showed considerable carbonate, proving that 
it undoubtedly came from the iron formation. 
This conglomerate has been traced pretty continuous! v for 
thirty-eighf miles in a semicircular belt around the central 
*Geol. of Can. 1863, pp. 53-4.. 
j-Hur. of Mines. Ont. 1889, viii, pp. 164-7. 
