TPIE FLORA OF THE SAINT EUGENE SILTS 



393 



Recent Post Glacial epoch. 



Valley alluvium. 



Delta deposits. 

 Pleistocene Wy cliff e Glacial epoch. 



Stage of glacial retreat. 



Marysville sands. 



Stage of glacial occupation. 



Wycliffe drift. 

 St. Eugene interglaoial (?) epoch. 



St. Eugene silts. 



"The Pleistocene deposits in the neighborhood of the Rocky Mountain trench 

 (Kootenay River valley) can be classified under two main heads, viz: the Wycliffe 

 drift, named after the town of Wycliffe on the branch line of the Canadian Pacific 

 Railway from Cranbrook to Kimberly, and the St. Eugene silts named after the 

 St. Eugene Mission. A detailed section, measured on the east bank of the St. Mary 

 River alx)ut 3 miles east of Wycliffe, gave the following results: 



Erosion surface 



Recent A. Stratified sand 15 feet. Marysville sands. 



Unconformity 



Pleistocene B. Till - 30 " Wycliffe drift. 



C. Stratified silt 25 " 



D. 



E. 



gravel 

 silt 



.15 



■ St. Eugene silts. 



F. Unstratifled coarse gravel (till?) 25 " 



G. Stratified sandy clay (fossil 



plants) 60 " 



H. Stratified gravels, lignite (base " 



unexposed) _ 60 " 



' ' Member G consists mainly of finely stratified silts and clay, with some gravel. 

 The more clayey members near the base contain, between the laminae, numerous well- 

 preserved plant remains of the Pleistocene. . . . 



' ' The St. Eugene silts occur over a large area in the Rocky Mountain trench and 

 are exposed along the cut banks of the Kootenay River at an elevation of about 2,800 

 feet. In the determination of the age of these silts the following facts are known: 



1. The silts are horizontal. 



2. They underlie uneonformably a till sheet. 



3. As far as known they are not underlain by a till sheet. 



4. They are well stratified and were deposited in quiet waters. 



5. They contain abundant plant-remains of the Pleistocene. 



" From these facts the silts may be : (1) pre-Glacial, and post-Tertiary ; (2) inter- 

 glacial, the underlying till sheet having been eroded away. 



"The age of these silts must at this stage remain an open question, as the only 

 fact which would prevent the silts from being post-Tertiary and pre-Glacial would be 

 the presence of a till sheet older than the silts. 



