Continuing to explore the coastline, the travelers find a passageway marked by Saknussemm as the way ahead, but unfortunately it has been blocked by a recent cave-in. The adventurers lay plans to blow the rock open with gun cotton, meanwhile paddling their raft out to sea to avoid the blast. On executing this scheme, however, they find a seemingly bottomless pit beyond the impeding rock and are swept into it as the sea rushes down the huge open gap. After spending hours descending at breakneck speed, their raft reverses direction and rises inside a volcanic chimney that ultimately spews them into the open air. When they regain consciousness, they learn that they've been ejected from Stromboli, a volcanic island located off Sicily.