"Light!" they exclaimed almost together.
They were looking through a tunnel made, as they afterward found, in the base of the filled-in portion of the chasm. Reptiles, bats and dust were forgotten now. Plunging forward on their hands and knees, the two boys advanced without difficulty to the distant mouth of the tunnel.
It ended abruptly in the face of the mesa cliff, one hundred feet above the valley below. There was not the slightest ledge below it and the side of the mesa dropped so precipitately that access to the tunnel mouth from without seemed impossible. The possibility of a climb to that entrance to reach the mesa above was out of the question.
The boys, panting for breath, lay on the floor of the tunnel with their heads just out of the opening.
"Some one has used this place, but how did they ever get up here?" asked Alan.
"I don't know and I don't care," said Ned with excitement. "But I do know that this entrance is concealed. Why, you couldn't even see it from below—it's so small. And it was made that way for a purpose. That must mean Cibola. Let's get busy."
There were one hundred and thirty-five steps to mount, and each was about a foot and a half high. When Ned and Alan were on top of the mesa again they were out of breath and their clothes were white with dust. They were also choked, thirsty and hungry.
"Eat heartily," laughed Ned, when they began breakfast over again; "we are going to have a busy day, I hope."
"What is your theory?"
"That our treasure is right here if it is anywhere," exclaimed Ned.