NO. I FORMATIONS OF BEAVERFOOT-BRISCO-STANFORD RANGE 21 



SUMMARY OF THE SINCLAIR SECTION 

 Silurian : Feet Meters 



Brisco 1.200 365.8 



Beaverfoot 400 121.9 



Ordovician : 



Wonah Quartzite no 33-5 



Sinclair 1,655 504-4 



Ozarkian : 



Mens 3,826 '■ 1,166.2 



Cambrian : 



Lyell ? 860 262.1 



Total section 8,051 2,453.9 



STODDART-DRY CREEK SECTION 



Section between Stoddart and Dry Creeks. The mouth of Stoddart 

 Creek Canyon is on the eastern side of the Columbia River \'alley, 

 7 miles (11.2 km.) north of Lake Windermere and 5.5 miles (8.8 

 km.) south of Sinclair Canyon. 



The mouth of the canyon is flanked on either side by a clifif of 

 massive-bedded, rough weathering, finely semi-crystalline, arenaceous 

 magnesian limestone. The dip on the north side is to the northeast 

 and on the south side slightly to the west-southwest. This limestone 

 dips beneath the shales and interbedded limestones of the lower 

 Mons formation, which extends to the north about one mile (1.6 km.) , 

 forming foot-hills up to the high cliffs of massive Silurian lime- 

 stones that constitute the eastern wall of the valley and the western 

 lower face of the Stanford Range. (See pi. 7, fig. i.) The shales 

 and limestones of the Mons dip to the northeast so that higher and 

 higher strata abut diagonally and successively against the , Silurian 

 (Beaverfoot) limestones. They are separated from the latter by a 

 fault which is a portion of a major fault line along the western side 

 of the Stanford Range. The Mons limestones and shales are a 

 portion of a large block that formerly extended far to the westward 

 prior to the erosion of the " Rocky Mountain Trench." It is about i 

 mile (1.6 km.) in length, north and south, and includes the Mons 

 section from near its upper limit down to the Briscoia zone at the 

 base. The basal Mons is superjacent to a massive-bedded limestone 

 that occupies the stratigraphic position and has the character of the 

 Upper Cambrian Lyell limestone of the Bow and Saskatchewan 

 A'alley sections to the north. West of the measured section, the Mons 

 is buried beneath the high Terrace drift gravels of the Columbia River 

 Valley. (See pi. 7, fig. i.) 



* In the Stoddart-Dry Creek section 5 miles (8 km.) south, the Mons is given 

 a thickness of 3,666 feet (1,117.3 m.). 



