50 SMITHSONIAN MISCELLANEOLTS COLLECTIONS VOL. 75 



Thickness. — Variable as it ranges from 42 feet (12.8 m.) to over 

 100 feet (30.4 m.) in a distance of 2 miles (3.2 km.). 



Organic remains. — No fossils found. A quartzite (Swan Peak) in 

 the Bear River Range of Northern Utah, occupying about the same 

 stratigraphic position, contains fossils that indicate its age as lower 

 Ordovician and probably Chazyan. (See p. 43.) 



Observations.— The Wonah Quartzite appears to represent the 

 beach sands of the transgressing waters at the beginning of Silurian 

 time in this area of the Cordilleran sea. It may be compared tenta- 

 tively with the quartzite described by Allan that occurs above the 

 Glenogle graptolite shales and beneath the Siluria;i limestones at the 

 northern end of the Beaverfoot Range.'' 



ordovician 

 Sinclair Formation 



Type locality. — Sinclair Canyon. 



Derivation. — Name derived from Sinclair Canyon. 



Character. — Thin layers of sandstone and arenaceous shale with 

 bands of silicious impure limestone in lower portion. 



Thickness. — At Wonah Ridge on Sinclair Mountain, the only local- 

 ity where the entire section was observed, 1655 feet (504.4 m.) 



Organic remains. — See p. 15. 



Observations. — It is not improbable that in No. i of the Sinclair 

 formation, the Glenogle shale graptolite fauna may be found. If it is, 

 then the 630 feet ( 192 m.) of No. i should be referred to the Glenogle 

 formation and the Sinclair correspondingly reduced in thickness. 



devonian 

 Messines Formation 



MIDDLE DEVONIAN 



Type locality. — Head of Glacier Lake Canyon valley above the 

 Mons Glacier and on the slopes of Mount Messines which rises above 

 the Mons icefield on the Continental Divide about 3 miles (4.8 km.) 

 southeast of Mount Mons, wdiich is about 50 miles (80.4 km.) north- 

 west of Lake Louise Station on the Canadian Pacific Railway, Alberta, 

 Canada. 



Derivation. — From Mount Messines. 



Character. — Dark, rough weathering, thick-bedded, clifif-forming, 

 magnesian limestone. 



^ Geol. Surv. Canada, No. 46, Geol. Ser. Memoir No. 55, 1914, pp. loi, 102. 



