“Yes,” agreed Tom, “we’ll have supper, turn in, and be up early to look for the tunnel.  We’re here at last.  I’ll dream of gold to-night.”

Eradicate soon had a meal in preparation, though he stopped every now and then to peer out at the bats, that still came in unbroken flight from the old temple.  Truly there must have been many thousands of them.

Whether Tom dreamed of gold that night he did not say, but he was the first one up in the morning, and Ned saw him hurrying over the sands toward the temple.

“Hold on, Tom!” his chum called as he hastened to dress.  “Where you going?”

“To have a hunt for that tunnel before breakfast.  I don’t want to lose any time.  No telling when Delazes and his crowd may be after us.  And the Fogers, too, may strike our trail.  Come on, we’ll get busy.”

“Where do you think the tunnel will be?” asked Ned, when he had caught up to Tom.

“Well, according to all that Mr. Illingway could tell us, it was somewhere near this temple.  We’ll make a circle of it, and if we don’t come across it then we’ll make another, and so on, increasing the size of the circles each time, until we find what we’re looking for.”

“Let’s have a look inside the temple first,” suggested Ned.  “It must have been a magnificent place when it was new, and with the processions of people and priests in their golden robes.”

“You ought to have been an Aztec,” suggested Tom, as he headed for one of the big doorways.

They found the interior of the temple almost as badly in ruins as was the outside.  In many places the roof had fallen in, the side walls contained many gaping holes, and the stone floor was broken away in many places, showing yawning, black caverns below.  They saw hundreds of bats clinging to projections, but the ugly creatures were silent in sleep now.

“Bur-r-r-r-r!” murmured Ned.  “I shouldn’t like any of ’em to fall on me.”

“No, it’s not a very nice place to go in,” agreed Tom.

They saw that the temple consisted of two parts, or two circular buildings, one within the other.  Around the outer part were many rooms, which had evidently formed the living apartments of the priests.  There were galleries, chambers, halls and assembly rooms.  Then the whole of the interior of the temple, under a great dome that had mostly fallen in, consisted of a vast room, which was probably where the worship went on.  For, even without going farther than to the edge of it, the youths could see stone altars, and many strangely-carved figures and statues.  Some had fallen over and lay in ruins on the floor.  The whole scene was one of desolation.

“Come on,” invited Tom, “it’s healthier and more pleasant outside.  Let’s look for that tunnel.”

But the lads soon realized that it was not going to be as easy to locate this as they had hoped.  They were looking for some sort of slanting opening, going down into the earth—­the entrance to the underground city—­but though they both made a complete circuit of the temple, each at a varying distance from the outer walls, no tunnel entrance showed.