Abstract
The Lewis Overthrust, famous structural geological feature, extends from Glacier National Park in Montana some 350 miles north into Alberta, Canada; is from 15 to 30 miles wide; and is believed to have been thrust eastward some 35 miles. This is often referred to in texts as a classic example of a large overthrust, but only one of many such observed throughout the world. Evidence for such overthrusting usually offered, is the inverted order of the fossil sequence in the strata, according to the assumed evolutionary advance of biological life during the geological ages, and so contained in the time-stratigraphic rock sequences from older to younger rocks.