lee. "You comin' back here?"

"Sure! But _over_ the mountain--not _under_ it."

Bud and his boy rancher chums remained that night at the store
settlement near the dam, getting beds in what passed for a hotel. It
was too late to secure horses and ride over Snake Mountain trail back
to Flume Valley.

While thus having a night of leisure, and seeing such sights as were to
be viewed in the little town, Bud and his chums discussed the queer
situation of the mysteriously disappearing and reappearing water. But,
talk as they did, and venture opinions as they and their cowboy friends
did, no one could hit on a solution.

"We'll just have to make another and more careful inspection," declared
Nort.

"That's what!" agreed Bud.

They learned from Slim that the situation regarding the cattle epidemic
at Square M ranch was not much better. All stock which had not been
exposed to the infection had been removed, either to Diamond X,
Triangle B or Flume Valley, and the infected steers remaining there
were being treated by a veterinarian whom Mr. Merkel had engaged.

"But they're slowly dying off," Slim reported. "And I don't believe
Square M ranch will ever be safe to use again."

"Why not?" asked Bud.

"Because there must be some infection in the grass there to have made
so many of the cattle sicken and die."

"Maybe it was something else," suggested Nort.

"Well, maybe," assented the foreman. "It's about as mysterious as that
underground river of yours. Had any more warnings, Bud?"

"No, I guess they're done with. And I believe it's a natural cause,
and not due to any work of enemies, that accounts for the queer way our
flume acts."

"Um!" spoke Slim musingly, and that was all he would say.

Borrowing horses from their friends, the boy ranchers next day made the
trip over Snake Mountain and returned to camp, finding matters there in
good shape. There was an abundance of water in the reservoir, and the
pipe was flowing freely.

For more than a week nothing happened. The cattle at Flume Valley,
including those of the boy ranchers, and the herd transferred from
Square M to save it from the epidemic, were doing well, abundant grass
and water being their portions.

There was no lack of hard work for the boys and their cowboy
assistants, for it was not all easy sailing. Occasionally bunches of
steers would stray, and have to be driven back by hard riding. There
were night watches to be carried on, and anot