“I wonder if the wind did it or the earthquake,” ventured Mr. Damon.

“No wind could do that,” declared Ned.  “It must have been the landslide caused by the earthquake.”

“The wind could do it if the ground was made soft by the rain; and that was probably what did it,” suggested Tom.

“There is no harm in settling the point,” commented Professor Bumper.  “It is not far off our trail, and will take only a few minutes to go over to the trees.  I should like to get some photographs to accompany an article that perhaps I shall write on the effects of sudden and severe tropical storms.  We will go to look at the overturned trees and then we’ll hurry on to camp to get the rescue party.”

The uprooted trees lay on one side of the mountain trail, perhaps a mile from the mouth of the cave which had been covered over, entombing the Beecher party.  Leaving the mules in charge of one of the Indians, Professor Bumper and his friends, accompanied by Goosal, approached the fallen trees.  As they neared them they saw that in falling the trees had lifted with their roots a large mass of earth and imbedded rocks that had clung to the twisted and gnarled fibers.  This mass was as large as a house.

“Look at the hole left when the roots pulled out!” cried Ned.  “Why, it’s like the crater of a small volcano!” he added.  And, as they stood on the edge of it looking curiously at the hole made, the others agreed with Tom’s chum.

Professor Bumper was looking about, trying to ascertain if there were any evidences of the earthquake in the vicinity, when Tom, who had cautiously gone a little way down into the excavation caused by the fallen trees, uttered a cry of surprise.

“Look!” he shouted.  “Isn’t that some sort of tunnel or underground passage?” and he pointed to a square opening, perhaps seven feet high and nearly as broad, which extended, no one knew where, downward and onward from the side of the hole made by the uprooting of the trees.

“It’s an underground passage all right,” said Professor Bumper eagerly; “and not a natural one, either.  That was fashioned by the hand of man, if I am any judge.  It seems to go right under the mountain, too.  Friends, we must explore this!  It may be of the utmost importance!  Come, we have our electric torches, and we shall need them, for it’s very dark in there,” and he peered into the passage in front of which they all stood now.  It seemed to have been tunneled through the earth, the sides being lined by either slabs of stone, or walls made by a sort of concrete.

“But what about the rescue work?” asked Mr. Damon.

“I am not forgetting Professor Beecher and his friends,” answered the scientist.

“Perhaps this may be a better means of rescuing them than by digging them out, which will take a week at least,” observed Tom.

“This a better way?” asked Ned, pointing to the tunnel.