The Volcano

There is no wondrous box-canyon, hidden near the Nahanni,

and termed "the Caribou Hole" in "Dangerous River";

nor is there a small cave on the Tlogotsho Plateau

containing charcoal remains of a prehistoric human presence.

And, an unseen footpath above the waters of Fourth Canyon

where one can line a canoe up to the Falls, doesn't exist.

But, is there a volcano somewhere between the Flat River

  and the main branch of the South Nahanni River?

Poole Field mentioned it in his earliest writings,

and R. M. Patterson actually did see it, himself.  Can you find it?