We have pretty clear and conclusive evidence that Southern Idaho, at least, has not been submerged in recent history.
We have over 600 square miles of bare lava and cinder cones deposited in the last 15,000 years. Among those lava fields are subterranean lava tubes open to the sky. These tubes are void of marine sediment, algae, or any other sign that they ever rested upon the ocean floor. Also present are cinder cones with no evidence of any sediment or marine life in the crater. The cinders and ash sit undisturbed just as the last eruption left them.
It is really an amazing sight, and everyone should make an effort to see Craters of the Moon if they have any opportunity.
