Utube has a lecture series dealing with the Pacific Northwest.
The last I saw dealt with "Ghost Volcanoes" those that once existed but died and eroded away.
The Cascade range is forty million years old, but the average Volcano exists for a average of two million years.
Many of the old ones are gone but they left traces, even totally erased they can be located by past lava flows.
In fact, when you see Granite you're seeing rock that was formed deep below a Volcano.
Last edited by Tracks; 03/07/21.
