“Exactly.”
The thought that they were really in a mighty submarine gold mine was a most thrilling one.
However, the professor had other points to gain now, so he left the gold vein and began some further explorations of the submarine cave.
This extended an unknown distance into the bowels of the earth.
The party did not venture to go far beyond the rays of the searchlight.
There would be great danger of getting lost in the labyrinth of passages, and certainly there would be no pleasure in this.
In view of the experiences of the professor and the captain, this was an issue to be avoided.
However, they carried the exploration as far as seemed safe.
This was a number of hundred yards from the submarine boat, and they began to think of returning when Barney stumbled upon an exciting adventure.
Suddenly he espied a curious-looking round body lying close to the wall of the cavern, and extending out of sight into dark depths.