It covered fully an acre. High above it was a funnel-like shaft. All in that instant Frank guessed the truth.
“By Jove!” he exclaimed, “I know where we are!”
“Eh!” exclaimed Randall.
“We are in the volcano!”
“The volcano?”
“Yes.”
“Impossible!”
“Not so! If you remember, we have traveled a good ways underground, and it has carried us without a doubt under the plateaus and straight into the heart of the mountain. Probably this is only one of half a hundred or more internal craters.”
The logic of this assumption was at once obvious.
Certainly in no other way could this crater of fire be explained. For a time the three men were silent.