80 



STRUCTURAL GEOLOGY OF NORTH AMERICA 



SHEEPROCK MTS. 

 Cohenour 1957 



EASTTINTIC MTS. 



Morris 1957 



S.STANSBURY MTS. 



Teicherl 1958 

 (modified) 



N. STANSBURT MTS. 



Arnold 1956 

 (modified) 



LAKESIDE MTS. 



Young 1955 



PROMONTORY MTS. 



Olson 1957 



LOGAN AREA 



Williams 1957 



Fig. 6.12. Ordovician, Silurian, 

 Devonian, and Mississippian forma- 

 tions of central and northern Utah. 

 Reproduced from Rigby, 1958. 



No reasonable doubt exists that rocks of the Cache Creek (Permian and 

 possibly in part Carboniferous) lie with profound unconformity over rocks of 

 the Shuswap terrain. Basal conglomerates of the Cache Creek contain boulders 

 of metamorphosed Shuswap rocks. Thus metamorphism and deformation of 

 the Shuswap rocks took place before the Permian. 



White (1959) sites a striking example of the basal Permian uncon- 

 formity in the Cariboo district. There, the Cariboo group of Early Cam- 

 brian age is closely folded into synclinoria and anticlinoria, and clastic 



members are regionally metamorphosed to the chlorite-muscovite grade. 

 The Slide Mountain group of Permian age of entirely different lithology 

 unconformably overlies the Cariboo group. It is mildly folded and not 

 metamorphosed. Because of the clear-cut relationship here, White pro- 

 poses the name, Cariboo orogeny, and includes all deformational events 

 from Early Ordovician to Pennsylvanian in it that occurred throughout 

 the entire Canadian Cordillera. 



Attention on previous pages to Devonian, Mississippian, and Pennsyl- 



