The mountain was originally formed in a narrow faulted rift ( running in a general south-east to north-west direction ) within the deformed and folded metamorphic rock ( arenite ) of the Hodgkinson Basin.
22.
For example, a quartz arenite would be composed of mostly ( > 90 % ) quartz grains and have little or no clayey matrix between the grains, a lithic wacke would have abundant lithic grains and abundant muddy matrix, etc.
23.
The Sioux quartzite was primarily formed by braided river deposits, of quartz arenite composition, with 95 % of the rock being composed of rounded, fine to medium ( 0.125 0.5 mm ) sand-size quartz grains.
24.
These three categories are : igneous or volcanic rocks ( basalt, granic, etc . ), sedimentary or deposit rocks ( limestone, sandstone, arenite, etc . ), and metamorphic rocks ( marble, slate, gypsum, etc . ).
