Pre-Cambrian Sections of Northwestern Montana and Northern Idaho , by C. D. Walcott 
Belt mountains, 
Montana (Walcott). 
Dearborn area, 
Montana (Walcott). 
Lewis and Clark 
area, Montana 
(Walcott). 
Lewis and Living- 
stone ranges, Mon- 
tana (Willis). 
Camp Creek, Mission 
Range section, Montana. 
(Walcott). 
North and Northeast of 
Coeur d’Alene, Idaho. 
(Calkins). 
Boundary section east 
from Kootenay river 
(Daly). 
Cambrian. 
Unconformity. 
No superjacent 
strata. 
Camp Creek series 
Arenaceous-grey 
1,762 feet. 
Cambrian. 
— Unconformity — 
Cambrian. 
Cambrian. 
— Unconformity. — 
Kintla. 
Sheppard Quartz- 
ites. 1, 200 feet. 
Calcareous and arenace- 
ous 
1,500 feet. 
Marsh . 800 feet. 
Arenaceous mostly red- 
dish colour 
Helena . 
Calcareous 
2,400 feet. 
Unconformity. 
Arenaceous 
1,015 feet. 
Siyeh limestone. 
Siliceous and calcar- 
eous. 
945 feet. 
Limestone, 285 feet. 
Greenish and purple, 
arenaceous and sili- 
ceous strata. 
Arenaceous 1,210 
feet. 
Empire. 600+ 
. Spokane. 1 , 500 + 
Greyson. 3,000+ 
Arenaceous strata 
5, 100 feet. 
Base concealed. 
4,000 feet. 
4,491 feet. 
No superjacent strata. 
5,772 feet. 
Total section 
2,540 feet. 
Grinnell. 
Appekunny 
Siliceous. 
3,800 feet. 
Arenaceous red and grey 
stone near 700 feet from 
summit. 
3,887 feet. 
Striped peak. 
2,000 feet. 
Newland. 
Calcareous 
2,200+ feet. 
Base concealed. 
Total section 6,718 
feet. 
Altyn calcareous and 
siliceous 
700 feet. 
Blackfoot. 
Calcareous and siliceous. 
4,805 feet. 
Wallace. Calcareous and 
siliceous. 
5,000+feet. 
Chamberlain. 
Siliceous 
1,500 feet. 
Base concealed. 
'Total section 
9,700 feet. 
No superjacent strata. 
Neihart sandstone 
700 feet. 
* 
Ravalli. 
Siliceous and arena- 
ceous. 
Purple and greenish and 
grey beds. 
8,255 feet. 
Yahk. 500 feet. 
Burke. 
Saint Regis. 
Siliceous aud arenaceous. 
Purple, greenish, and grey 
beds. 
8,000 feet. 
Archcean. 
Total section 
12,000 feet. 
Moyie. 
Argillite. 
3,200 feet. 
Kitchener. 
Quartzite. 
Base concealed. 
Total section 
24,760 feet. 
Prichard. 
Banded, dark blue grey, 
blue black and grey. 
* 
7,400 feet. 
9 
Siliceous series. 
10, 000 feet. 
Creston. 
Quartzite. 
Base concealed. 
Total section 
25,000 feet. 
9,500+feet. 
1 
j 
Base concealed . 
Total section 
20,600 feet. 
Total thickness of section of Pre-Cambrian rocks in northwestern Montana and Northern Idaho, as now known, 37,000 feet. 
56815— p. 88a. 
