 In geology, the range has more in common with the Coast Ranges of British Columbia and Alaska than it does with its Cordilleran cousins in the Rocky Mountains or Sierra Nevada.Although the peaks of the North Cascades do not reach great elevations (high peaks are generally in the range, their overall relief, the relatively uninterrupted vertical distance from valley bottom to mountain top, is commonly .Rocks of the North Cascades record at least 400 million years of history.