"Hard luck, Paul," Frank told him, on taking a look at the painful joint. "You've gone and knocked that ankle against a root or a rock, and if you're wise you'll lay low for a couple of days." So when the others started forth with fair hopes of accomplishing something worth while, poor Paul was left to tend camp. "Be sure and make your way up to the corral along toward noon," Lanky told him: "so as to see that our ponies are O.K.--that is, if your ankle lets you limp that far." "No trouble about it, I guess," returned the chagrined Paul, who naturally did not like to be left behind when his chums were going to be in harness and do some exploring. "Cook yourself a fat lunch, too," advised Lanky, feeling sorry for the disappointed boy. "It'll help pass the hours away. At most, we expect to show up some time before sundown. By-by! Keep an eye out for those tough men, though I don't believe they mean to return here for days, if ever." So Frank and Lanky went off, never dreaming that they were fated to pass through another wonderful experience before again setting eyes on the chum they left behind. Lanky and Frank learned just where the others had done most of their looking for the so-called Lost Mountain, in the depths of which, they understood, was the five-fingered cave that Josh Kinney used to visit regularly, to replenish his depleted treasury by a fresh haul from his deposit of gold nuggets. Before leaving the camp Lanky and Frank, between them, had laid out a plan of campaign. Following this they now set off on a tangent with the course taken a short time before by Mr. Wallace, Jerry Brime and Zander Forbes. "We'll try out our scheme," Lanky declared later on, as they continued to walk along; "and then if it fails to bring results, why, to-morrow we can skirmish over in the region they've been combing day after day." The morning passed, and so far the boys had not run across a single thing to give them encouragement. "We don't seem to be getting anywhere," observed Frank. "Let's swing more to the left, along this dip in the mountain," suggested Lanky. "Then we'll be gradually getting back to camp, and at the same time nearing the region where dad and his gang are working. "It's mighty wild and leery looking over in that quarter," observed Frank. "Looks to me as though Nature had tried to turn things upside down many a time, in days long passed. Been landslides, too, that have changed the whole face of the country, carrying acres of trees and rocks down the mountain." "That's one reason," observed the other eagerly, "I want to hunt there for the Lost Mountain which, you know, we decided was only a big mound. Remember, we figured it out from certain marks on the map that they stood for landslides? Let's go, Frank." "A snack first, for I'm hungry, and then we're off," came the reply. "All right. I've never yet declined to eat," laughed Lanky.