NO. 5 PRE-DEVONIAN PALEOZOIC FORMATIONS 263 



of the tests of trilobites were seen on freshly broken surfaces. The 

 cliff is about lOO feet (30.5 m.) high, and is formed of contorted and 

 broken layers, dipping roughly toward the river, where, broken down, 

 they form a steep slope to the river. 



The slope above the cliff is covered with soil for 100 feet (30.5 m.) 

 or more to ledges of darkish gray, coarse-weathering limestones, evi- 

 dently a part of the Middle Cambrian limestones that form the east- 

 ward-facing cliffs at the summit of Marsh Mountain. From the 

 position and character of the lower sandstones and shales it is highly 

 probable that they represent the arenaceous beds of the upper portion 

 of the Lower Cambrian beneath the Mount Whyte series of the Mount 

 Bosworth section. If this interpretation is correct, the Cambrian 

 section of the Front Range between the south fork of Ghost River 

 and the south fork of Panther River, and probably still farther north- 

 west, includes the St. Piran and Mount Whyte formations of the 

 Lower Camljrian, and the Ptarmigan formation of the Middle Cam- 

 brian, with which the section terminates above at a plane of discon- 

 formity resulting from the non-deposition in this region of the missing 

 Middle and -Upper Cambrian and later formations up to the Devonian. 



SAWBACK RANGE AREA 



The Ordovician, Ozarkian, and Cambcian strata examined by me 

 in the Sawback Range continue on the same strike from the northeast 

 side of the Bow Valley 6 miles (9.7 km.) northwest of Banff, to the 

 north side of the head of Clearwater Canyon, a distance of about 

 50 miles (80.5 km.). The strata are upturned to the northeast and 

 dip to the southwest from 65° to 75° along the Bow Valley and from 

 25° to 75° southwesterly at various points along the line of their 

 outcrop to the northwest. The Canadian Sarbach formation is usually 

 directly subjacent to Middle Devonian limestones from the Bow 

 Valley northwest as far as Saskatchewan River. An exception occurs 

 on the northeast shoulder of Fossil Mountain, where the Ordovician 

 Skoki formation occurs between the Sarbach and Devonian (F on 

 map, pi. 26). Below the Sarbach the section extends down through 

 the Ozarkian Mons formation and the Upper Cambrian into the 

 Middle Cambrian Fldon limestone. In the Ranger Canyon section (H 

 on map) an over-thrust fault has carried this belt of strata up against 

 the outcrop of a second block of Devonian limestone on the northeast 

 side of Upper Ranger Canyon. The section extends down into the 

 Eldon limestone from Ranger Canyon to the Red Deer River and 

 probably still farther to the north-northwest. The Eldon limestone 



