sentences:  Big Cave lies at the northern end of a belt of late, Quaternary volcanoes moving north from Lassen Peak.It is a small shield volcano, likely formed during the Holocene epoch, though scientists from the United States Geological Survey are unsure.It could also be from the late Pleistocene epoch; M. A. Clynne thought it may be of similar age to the nearby Cinder Butte volcano, at 38,000 ± 7,000 years.