The four needed no second warning. The next moment they were shooting into the crawling monsters right and left.
"Clear a path to the rock!" shouted Joe, who was doing his part of the shooting.
His advice was promptly acted upon, and half a minute later Jack and Joe dropped from their perch and rushed to the side of their friends.
Leaving the fire still burning brightly on the top of the rock, all hands rushed through the passage and soon reached the cave where the skulls and bones lay in such numbers.
Strange to say, none of the huge land crabs followed them, nor did any more of the strange animals appear.
In a very short time Van led the way to the incline, where he and his three companions had slid down in such an unexpected manner.
By dint of the greatest exertion, they managed to crawl up the slippery place.
"Now, then," observed Lank Edwards, "we are all right till we strike ther dwarfs."
"I think we can get the best of them if we keep our eyes open," returned Jack. "'Lead on, Van."
With their weapons ready for instant use, they proceeded along the passage.