Accumulation of large basaltic boulders downstream of plunge pools at Dry Falls State Park. Dry Falls is a great cataract 3.3 miles wide and 396 feet high that formed during the cataclysmic late Pleistocene floods emanating from glacial Lake Missoula in Montana. The origin of the Channeled Scablands was the subject of one of the most famous controversies in the history of geology. When J. Harlen Bretz formulated the cataclysmic flood hypothesis in 1923, his ideas were rejected. Nearly 50 years passed before his ideas became a standard of geologic thinking. In 1979 and at nearly 90 years of age he was awarded the Penrose Medal of the Geological Society of America, the nation's highest geological award.
Some more bio
J Harlen Bretz (they neither put a period after his first initial nor explain why it isn't there) was a superb field geologist, one determined to see what was there rather than what theory predicted should be there---a rare and valuable talent in any scientist.