"How far away are they?" asked Tad.

"More than forty miles," answered Dad. "You wait till we get to the
edge. You can't tell anything about those buttes now."

"What is a butte---how did they happen to be called that?" asked Walter.

"A butte is a butte," answered the guide.

"A butte is a bump on the landscape," interjected Stacy.

"A butte is a mound of earth or stone worn away by erosion," answered
the Professor, with an assurance that forbade any one to question the
correctness of his statement.

"Yes, sir," murmured the Pony Rider Boys. "A wart on the hand of fair
Nature, as it were," added Chunky under his breath.

"Come, we must be on our way," urged Dad. "We want to make half the
distance to the Canyon before night. I reckon the pack train will have
gone on. We'll have to live on what we have in our saddle bags till
we catch up with the train, which I reckon we'll do hard onto noon."

No great effort was required to descend Sunset Mountain. It was one
long slide and roll. The boys screamed with delight as they saw the
dignified Professor coasting and taking headers down the cinder-covered
mountain.

By this time the clothes of the explorers had become well dried out in