NO. 5 PRE-DEVONIAN PALEOZOIC FORMATIONS 29T 



crops of calcareous shale and bluish-gray limestone of 

 the Mons occur as scattered ledges down to the stream 

 bed. See p. 284 for note on outcrops in Baker Creek 

 Canyon Valley. 



Tilted Mountain Brook Section 



Tilted Mountain is 1.7 miles i^^.y km.) east-northeast of Brachio- 

 pod Mountain, about 2 miles (3.2 km.) southeast of Fossil Moun- 

 tain (see F on map, pi. 26), 2.8 miles (4.5 km.) south-southeast of 

 Oyster Mountain, and 9.5 miles (15.3 km.) east of Lake Louise 

 Station on the Canadian Pacific Railway. 



Tilted Mountain Brook flows from a small glacial lake in the bottom 

 of a large cirque through a channel eroded in the upper Lyell mag- 

 nesian limestones and down through the calcareous shales and lime- 

 stones of the Sabine formation. It enters the broad upper canyon 

 valley of Baker Creek, about .5 miles (.8 km.) west of the small 

 lake, the waters of the brook sliding and falling over the thick 

 magnesian limestone layers that form the first sloping clift" above the 

 broad bottom of Baker Creek Canyon. A diagrammatic section of this 

 portion of the section is shown by figure 26. About 130 feet (39.6 m.) 

 down from the base of the Mons the upper zone (2od) of the Sabine 

 fauna occurs, and below this the typical Franconia FtycJiaspis fauna, 

 in the midst of which the Collcnia zone occurs. It gave us a thrill of 

 delight when these faunules were discovered, ending the long search 

 at this horizon for a distinct fauna. 



The Collcnia zone was traced north to a point below Cotton Grass 

 Cirque, opposite Fossil Mountain. 



This section is essentially the same as that at Cotton Grass Cirque 

 1.5 miles (2.4 km.) to the north, at the south end of Oyster Peak 

 Ridge (see p. 285), except that the upper fossiliferous portion of the 

 Sabine formation is not well developed west of Cotton Grass Cirque. 



UPPER CAMBRIAN 



The Mons formation extenas across the floor of the canyon valley 

 east of Baker Lake to the west base of Tilted Mountain. 



Sabine Formation t? . at . 



Feet Meters 



la. Gray, hard, arenaceous shale, with interbedded thin 



layers of arenaceous dolomitic limestone 15 4.6 



lb. Thick-bedded, hard, rough-weathering, gray and buff 



dolomitic limestone 115 35.0 



ic. Light gray, thin-bedded, somewhat irregular limestone. . 16 4.9 



