21 
(45) A fine-grained, thin-bedded dolomite, weathering brownish and fractur- 
ing across the bedding plane. It originally contained many fossils, but solution 
and much minor slickensiding have made all organic remains unidentifiable, 
except some impressions. The rock contains small geodal cavities and becomes 
pitted upon weathering 25 feet 
(46) Alternating coarse to medium-grained and medium-bedded dolomite. 
The upper 150 feet contains geodal cavities and becomes pitted upon weathering. 450 feet 
(47) A coarse-grained dolomite with many geodal cavities 80 feet 
Fossils rare. 
Section S 
This section was rather hurriedly made along the western slope of 
mount Aylmer at the western edge of the head of Aylmer canyon. 
Spray River Shale (Triassic) 
The lower beds of this formation are well exposed just at the left of 
the trail up the mountain as it passes up the first steep slope upon leaving 
the usual summit camping place. The transition from the shale to the 
Rocky Mountain quartzite is here plainly seen, with the two formations 
apparently conformable. 
(1) Thin-bedded, dark grey shales, weathering brownish red 220 feet 
(2) Black to grey flags 15 feet 
(a ) Black Bhaly flags 12 feet 
(b) Light grey shaly flags with a few iron concretions 3 feet 
Rocky Mountain Quartzite ( Permian ) 
(3) Quartzites 14 feet 
(а ) Dark grey quartzite very full of iron concretions. It is unevenly bedded, 
with an uneven surface „ . . 2 feet 
(б ) Dark grey quartzite; no concretions noted. The upper part has a very 
uneven surface 10 feet 
(c ) Farther up the slope along the strike of the junction of the shale with 
the quartzite were noted several large angular bouldfers of a white quartz 
containing Euphemus carbonarius arenarius and Plagioglypta canna. 
These boulders, although not in place, were probably not much more than 
10 feet below 3 a 2 feet 
(4) Quartzites and dolomitic limestones. 
(a) Quartzites and dolomitic limestones not measured ? feet 
(b) Thin-bedded quartzite 10 feet 
(c) Mostly heavy-bedded sandstones, weathering brownish. The basal bed 
is a dark friable shale 38 feet 
Rundle Limestone (Upper Part) ( Lower Pennsylvanian) 
(5) Limestones and shales 75 feet 
(a) Grey limestone above; the lower half a friable greenish shale 25 feet 
(b) Greenish shales similar to 5 a 12 feet 
(c) Light grey dolomitic limestone .*. . . 38 feet 
(6) Light grey to dark grey dolomite 37 feet 
(a) Light grey cherty dolomite 12 feet 
(b) Dark grey dolomite, including thin, very irregular black shale bands. 
The lowest 2 feet weather purplish, with an included greenish shale band 
of 3 or 4 inches width 25 feet 
Fossils are abundant in the purplish beds. 
(7) Black limestones and calcareous shales 74 feet 
(a) Very dark grey limestone 24 feet 
(b) Compact, dark grey to black calcareous shale, at times chert-bearing. . . 50 feet 
In both uppermost and basal beds are many specimens of Produclus cora ; 
the cross-sections of the white shells are conspicuous in the black rock. 
