“Who’s there?” asked the young inventor sharply, as he reached for his electric rifle.

There was no answer, but a rattling of the pans.

“Speak, or I’ll fire!” Tom warned, adding this in such Spanish as he could muster, for he thought it might be one of the Indians.  No reply came, and then, seeing by the light of the stars a dark form moving in front of the tent occupied by himself and Ned, Tom fired.

There was a combined grunt and squeal of pain, then a savage growl, and Ned yelled: 

“What’s the matter, Tom?” for he had been awakened, and heard the crackle of the electrical discharge.

“I don’t know,” Tom answered.  “But I shot something—­or somebody!”

“Maybe some of Beecher’s crowd,” ventured his chum.  But when they got their electric torches, and focused them on the inert, black object, it was found to be a bear which had come to nose about the camp for dainty morsels.

Bruin was quite dead, and as he was in prime condition there was a feast of bear meat at the following dinner.  The white travelers found it rather too strong for their palates, but the Indians reveled in it.

It was shortly after noon the next day, when Goosal, after remarking that a storm seemed brewing, announced that they would be at the entrance to the cavern in another hour.

“Good!” cried Professor Bumper.  “At last we are near the buried city.”

“Don’t be too sure,” advised Mr. Damon, “We may be disappointed.  Though I hope not for your sake, my dear Professor.”

Goosal now took the lead, and the old Indian, traveling on foot, for he said he could better look for the old landmark that way than on the back of a mule, walked slowly along a rough cliff.

“Here. somewhere, is the entrance to the cav-ern,” said the aged man.  “It was many years ago that I was here—­many years.  But it seems as though yesterday.  It is little changed.”

Indeed little did change in that land of wonders.  Only nature caused what alterations there were.  The hand of man had long been absent.

Slowly Goosal walked along the rocky trail, on one side a sheer rock, towering a hundred feet or more toward the sky.  On the other side a deep gash leading to a great fertile valley below.

Suddenly the old man paused, and looked about him as though uncertain.  Then, more slowly still, he put out his hand and pulled at some bushes that grew on a ledge of the rock.  They came away, having no depth of earth, and a small opening was disclosed.

“It is here,” said Goosal quietly.  “The entrance to the cavern that leads to the burial place of the dead, and the city that is dead also.  It is here.”

He stood aside while the others hurried forward.  It took but a few minutes to prove that he was right—­at least as to the existence of the cavern—­for the four men were soon peering into the opening.