[glorgau]

I remember seeing a theory that the Great Basin in the cental U.S. was formed by a huge lake

See Fort Rock, OR. The wave terraces are about 150 feet up.

[trad_anglican]

See Fort Rock, OR

Thanks!

[VanShuyten]

There were several ice dam and other huge lakes after the last ice age. Lake Bonneville in Utah is another example. As you drive along the interstate going south, you can see the old shoreline up on the side of the mountains.

I'm pretty sure there was a large one in eastern Washington, too.