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



the quartzite extends to where a northwest-southeast fault brings 

 the upper beds of the Ozarkian (Mons formation) against it. The 

 first faunule found in the Alons, going down, was just below 

 bridge No. 4, and this faunule is repeated (i6q, p. 17) just above 

 bridge No. 3, which is 5,400 feet (1,645.9 ^■) down the canyon 

 from No. 4. The layers of limestone and shale are highly inclined 

 and it is quite possible that an anticline occurs between bridges 

 3 and 4. Below bridge 3 the Silurian extends down the canyon about 

 4,400 feet (1,341.1 m.) to the clififs of Red Wall Fault Breccia. (See 

 pi. 3.) West of the Red Wall Fault a thick-bedded, cliff-forming 

 magnesian limestone of possible Upper Cambrian age occurs that is 

 subjacent to a series of shales and interbedded layers of limestone 

 that contain the lower Mons fauna, and the sequence of the Mons 

 faunules is continuously upward until the upper middle Mons 

 faunule (21 f) or Hnngaia faunule is met with just east of the pink 

 weathering Silurian limestone forming the Gates of Sinclair Canyon. 

 (PI. 2, fig. 2.) 



The Sinclair Canyon section beginning at the summit of Sinclair 

 Mountain and passing down to the lowest beds exposed is necessarily 

 made up- of parts occurring in the canyon between the great faults. 

 The greater portion of the Mons formation is found between the 

 Radium Hot Springs and the. Gates of the Canyon. A concealed 

 portion of the upper Mons formation is inserted from the Stoddart- 

 Dry Creek section as it occurs 5 miles (8 km.) to the south. 



silurian 

 Brisco Formation : -^ . ^, 



reet Meters 

 I. Thick-bedded (2 to 6 feet, .6 to 1.8 m.) dark gray rough 

 weathering and more or less silicious magnesian lime- 

 stones forming cliffs and high points. (Estimate) 1,200 365.8 



Fauna. — The fauna in the basal portion of the Brisco 

 (Silurian) is scant, consisting mainly of very poorly 

 preserved cyathophylloid corals. However, within 50 

 feet above the top of the Beaverfoot (Richmond) in 

 the Windermere Creek section Pentamerus was found. 

 Slightly higher stratigraphically but below the Mono- 

 graptus horizon Virgiana was found in abundance in 

 Sinclair Canyon. In the upper portion of the Silurian a 

 more abundant fauna was collected near the head of 

 Windermere Creek which included (E. Kirk) : 



Halysites sp. 



Syrhigopora sp. 



Favosites sp. 



Atrypina sp. 



Spirifer sp. 



Stropheodonta sp. 



