a piece of paper was taken from his pocket by
John. Upon it he wrote, "The grave of an unknown man, supposedly Simon
Moultrie. The bones were found July 13, 1914, by Fred Button, John Clemens
and Zeke Rattray."

"Don't you think," inquired John, "that I had better put our addresses on
this paper too?"

"Good scheme," replied Fred.

Accordingly the permanent address of each member of the party was added to
the brief statement.

"Do you suppose we'll ever hear from anybody?" inquired John in a low
voice.

"I don't know," answered Fred, shaking his head as he spoke. "It's one of
those things you never can tell about."

Fred Button was one of the four boys who among their friends and
themselves, for the matter of that, were commonly known as the Go Ahead
Boys. They were schoolmates and classmates and were nearly of the same
age, John being the only one who was eighteen, while his three companions
were each seventeen years old.

In various parts of their country they had been spending their recent
vacations together. The list of books given at the beginning of this story
will indicate the various parts of the country in which they had met their
adventures.

At the present time, however, when this story opens, they were nearly two
thousand miles from home.

Across the continent they had journeyed together and together also they
had spent ten days viewing the wonders of the Grand Canyon of the
Colorado. The apparently perilous ride on the backs of donkeys down Bright
Angel Trail had been greatly enjoyed, as well as certain other inspiring
expeditions which the boys had made, sometimes in company with others and
sometimes with a single guide for the quartet.

So enthusiastic had the young travelers become over their experiences that
at last they had obtained the consent of their parents to make an
expedition of their own. Two guides were secured who were familiar with
the entire region and two strong skiffs were purchased. In these boats the
boys had planned to follow a part of the dangerous Colorado River. They
had no desire to incur the perils that belonged to many of its swirling
rapids and tossing waters. In other places, however, the river was
comparatively safe and there the boys planned to follow the course of the
stream with their strong and heavy little boats.

Inasmuch as Fred's father was a prominent railway official he had obtained
for the boys certain privileges which otherwise they might not have had