34 F 
EKWAN niVER. 
Sandst<m&^ 
and sUtPS iin- 
prpCTiatpd 
with iron 
oxides. 
Rock.s similar 
to the Aniini- 
kie of Tlum- 
der bay. 
and it i.s only in such an erosion valley as that of the lake above re- 
ferred to, that expo.sures of the beds beneath the trap can bo scon. 
In the vicinity of .Sutton Mill lakes the series is nearly horizontal, 
inclining slightly to the north toward the basin of Hudson bay and 
as oxpo.sed consists of a thickness of 90 feet of sandstone and .slates, 
capped by an extrusivo trap showing a thickness of 150 feet. The 
sandstone.s and slates here, o-s well n.s on the Labrador ponin.sula, are 
impregnated with iron oxides ehieily in the form of magnetite and 
hematite. The sandstone.s expo.sed are comj) 0 .sed of i-oundcd and 
flattened grains of a reddish chalcedonic quartz surrounded by a slight 
deposit of the iron ore, and the interspiices are filled by a fine mosaic of 
quartz. In tlie darker coloured rock the gi'ains are surrounded, and in 
parts replaced, by luagnetite, while the interstitial quartz is less in 
amount. The appearance of the beds is that of a handed jasper, con- 
si-sting of red beds separated by munerous narrow .seams of a dark 
.slate. On .smooth surface.s the individual grains of the sandstone are 
distinctly shown. The slates which occupy the upper part of the 
section are made up of minute fragments of (juartz, both red and 
colourless, forming 50 per cent of the mass, while the remainder is 
made up of a series of opaque particles which, from the result of an 
analysis of the rock, is probably largely magnetite. 
These rocks, when .•omp.ared with tlioso from the Animikie of Tliun- 
der hay, ’present many features in common. Their description as given 
by Mr. E. D. Ingall (Annual Ueport, Geo. .Surv. Can., vol. Ill, p. 81 
H.) shows that the general character is very much the same, but in 
the button Mill lakes rocks the calcareous ami doluinitic portions are 
wanting or have been replaced, 'fhe only mineral of economic impor- 
tance ob.served in this series is iron. Magneiic ores of this meial are 
freely distributed througliout the wlu.»le of the section of the stratified 
serie.s, but the fact that tlies(? ore.s are not generally concentrated 
in thick enough beds would count against their practical value. 
Closer examination might show that the richer part.s of the section 
could be profitably worked. A few specimens from tbi^ exjiosure were 
lirougbt in to the laboratory, and analyses of three were made. These 
are from the upper part of the section, the centre, and the lowest bed. 
The analyses of the three samples, as furnished by Dr. G. C. Hoflinann, 
are given below : — 
I'Vom the upper bed — 
Metallic iron 33 • 40 per cent. 
Tn.soluble siliceous residue 48'49 “ 
Titanic acid none 
