Abstract
In the southwest part of Alberta, Canada, the eastern Rocky Mountains have been considered to be fault blocks in which most of the faults, as interpreted, remain separate at depth. In the adjoining foothills to the east of the mountains drill holes show that many faults join at depth into sole faults which in relatively incompetent beds closely follow bedding planes and in more competent beds diagonally cut across the bedding. This is step faulting as described by Rich in the southern Appalachians in which the faults are directly related to the beds that are intersected. Recent drilling in the Livingstone Range of Southern Alberta has shown that this mountain is composed of superimposed folded fault slices. It is believed that the folding resulted from the faulting and is not necessarily subsequent to the faulting as has been generally assumed. The eastern Rocky Mountains, as typified by the Livingstone Range, may be composed of superimposed folded fault slices rather than individual fault blocks as has been formerly thought.
