“not very much fun—this,” commented rick, as he and chot tossed rock after rock aside. “like prisoners working on a stone pile; isn’t it?”

“oh, i don’t know,” slowly answered chot, as he straightened up to ease his aching back. “we don’t have to do it if we don’t want to, rick.”

“yes, that’s so,” agreed the other lad. “here, ruddy, what are you trying to do?” he asked, for the setter was acting in a peculiar manner standing at attention in front of a hole that ran under the roots of a gnarled tree. ruddy was growling in a low voice and he showed every indication of anger, not unmixed with alarm.

“let’s go over and see what he’s got,” suggested chot.

“i only hope it isn’t a skunk,” murmured rick. “he fooled me that way once and—whew—i’ve never forgotten it! oh, boy!”

“i don’t smell anything,” remarked chot, hopefully.

“no, not yet,” assented rick with a laugh. “and when you do smell it—then it’s too late. but i reckon it isn’t a skunk. if it was he’d have been into action long before this. mr. skunk doesn’t stand much monkeying. he’ll give you two fair warnings before he shoots and then, if you’re foolish enough not to mind them he unlimbers his heavy artillery. here, ruddy, keep back until i can see what it is under there!” ordered rick.

the dog looked toward the boys as they left the stone pile, growled again and then obediently moved away from the hole into which he had, evidently, seen some animal retreat, or perhaps he had chased it there himself, since rick and chot had not paid much attention to him.

the two boys cautiously approached the hole under the roots of the old, gnarled tree which grew out of the side of the hill not far from the pile of rocks. as he drew near rick began sniffing the air cautiously, for, as he said, he had had one experience with a skunk that ruddy stirred up, and did not want another.

“there’s a wild animal smell, but i don’t believe it comes from a skunk,” was rick’s opinion as he drew near the hole. “can you reach me a stick, chot?”

“here,” answered his chum, passing over a long slender tree branch. rick poked it down in the hole, turned it around and jabbed it in as far as it would go. nothing came out, not even a sound.

“guess it’s a false alarm,” suggested chot.

“maybe so. yet ruddy isn’t the kind of a dog to bark up the wrong tree or down the wrong hole. maybe the stick isn’t long enough.”

the lads looked around until they found a larger pole, ruddy, meanwhile, watching them curiously and interestedly. but though rick and chot took turns poking sticks down the hole, turning them this way and that, and jabbing them in, not a sound—not a growl or snarl—came out from among the twisted roots.

ruddy stood near his two friends, made little darts forward at the hole at every motion on the part of the boys, and whimpered in eager anticipation, growling now and then and, anon, permitting himself the challenge of a bark. but it was all to no purpose.

“i guess there’s nothing here,” said chot at last. “we’d better get back to our stone pile.”

“there has been something here,” said rick. “i can smell that wild animal smell.”

“like in a circus tent,” suggested chot.

“that’s it—sure! but whatever it was has gone out i reckon.”

“animals have back doors to their dens; don’t they?” asked chot.

“i reckon they do—this one must have had, anyhow.”

“what do you think it was, rick?”

“oh, a fox, maybe.”

“couldn’t it be a bob cat?”

“you mean a lynx?”

“yep.”

“sure, it could. maybe it was. well, we’ll let it go this time, seeing it got away!” laughed rick. “come on, ruddy, chase yourself around and get up an appetite for dinner,” and he threw a stick down the side of the hill, the boys laughing at the dog’s eagerness to retrieve it.

“do you mind doing this, chot?” asked rick, when they were again busy on the stone pile, tossing and prying aside the rocks.

“not a bit—why?”

“well, it isn’t much fun to ask you out west on a vacation and then set you to heaving rocks.”

“we aren’t doing this for work—it’s because we want to find out something,” declared chot. “i don’t mind if you don’t.”

“no, i don’t. if we can only show uncle tod how to get back the water of lost river—cracky! wouldn’t he be surprised?”

“i’ll say he would!” ejaculated chot.

it was no easy task the boys had set for themselves, for the stone pile was large, and many of the boulders in it were of great size. but they were scouts and not accustomed to give up a task just because it was difficult.

the smaller stones they tossed out of their way, and the larger ones, some only after many trials, were rolled down the side of the valley after being dislodged by tree-branch levers.

once, just before noon, chot straightening up to ease his back, looked toward the hole under the twisted tree roots.

“there’s ruddy at the bob cat’s den again,” he remarked.

“i’m not sure it’s a bob cat,” said rick, “but he certainly is there,” and he looked toward where ruddy was now trying to enlarge the hole by digging away the dirt at the lower edge. “come here, ruddy!” called rick.

the dog barked, came a little way toward his master, reluctantly enough, and then returned to the hole.

“he hates to leave it,” said chot.

“must be something there,” agreed his chum. “we’ll set a trap there to-night.”

“where’ll we get a trap?”

“oh, uncle tod has some. i’d like to catch something.”

“so would i, if it isn’t a skunk,” said chot.

“well, after all, it may only be a big rat, or some animal like a groundhog,” decided rick, “though i don’t know whether groundhogs live out here or not. all right, ruddy,” he went on, speaking to his dog, “stay there if it’s any fun, and let us know when it comes out.”

again the boys fell to work on the stone pile. they could see that they were making an “impression” on it, as rick called it when they stopped to eat some of the lunch they had brought with them, sharing it with ruddy. for there was quite a hole excavated into the pile of big and little boulders.

after their meal, which was followed by a brief resting period, the lads again began tossing aside the rocks in their endeavor to see what lay behind them. that it was the opening into a tunnel beneath the mountain they hoped. and what they feared was that the pile of stones might hide but the smooth gravel side of the sloping hill.

“but it can’t be that,” decided rick. “these stones never got here naturally. they were piled here and there aren’t any like ’em anywhere else around here.”

“where do you think they came from?” asked chot.

“from inside the tunnel that we’re going to find,” was rick’s ready answer. “the stones were blasted out of the tunnel and piled here to cover up a hole, i’m sure.”

“maybe so,” agreed chot.

it was about the middle of the afternoon that chot, again straightening up, looked at his hands and asked, ruefully:

“what’s good for blisters, rick?”

“you getting some?”

“sure! aren’t you?”

“a few, yes. say, what we ought to have are leather gloves, or leather pads like those the men wear when they’re paving a street with granite blocks.”

“all right, chase down to the five and ten cent store and get a couple of pairs,” chuckled chot as he gazed around on the deserted and desolate valley, for not a human habitation was in sight.

rick looked at chot a moment, as if he did not understand, or was not thinking of what his chum was saying. then rick cried:

“i have it—bark gloves!”

“bark what?” asked chot.

“bark gloves! look, we can peel off some bark from this tree—it’s tough and stringy. we can take a piece, cut a hole in for our thumb, and tie the bark on with string. that will save the palms of our hands.”

“that’s a good idea!” complimented chot. “let’s try it.”

with their knives they stripped some bark from a tree, the name of which they did not know, but which bark was sufficiently tough and pliable to form a protective covering. tying pads of this on their hands saved them from most of the contact with the rough stones, and the boys were able to work much faster now.

they paid little attention now to ruddy, though occasional glances showed them that the dog was still worrying away at the hole. he growled and whined, looking occasionally toward his two boy chums as if he could not understand why they did not take the same interest as did he.

but rick and chot had other matters to occupy their attention. they could see, now, that they were making an opening through which was, undoubtedly, a screening wall of stones. they did not have to toss aside the rocks all the way to the top, for near the summit some great boulders had fallen, or been placed, in the shape of a rude arch, supporting themselves and the stones above and on either side.

“if we get enough of these lower stones out of the way,” remarked chot, “we can walk under the arch just like through a gateway.”

“if it doesn’t fall on us,” agreed his chum, a bit apprehensively.

but neither boy dreamed of danger. faster and faster they worked as they saw the afternoon sun waning, and when its shadows were very long suddenly rick pulled aside a large stone and gave a cry.

“hurry!” he shouted. “here it is, chot!”

“what?” asked the other, who had gone to the water bottle for a drink.

“the tunnel! it’s here all right, and some one piled these rocks here on purpose to hide it. now let’s see if we can find lost river!”

chot and rick stood side by side, gazing into the dark opening that had been revealed to them. more rocks were quickly tossed aside. a larger opening was seen.

“shall we go in?” asked chot as they peered into the murky blackness.

rick did not answer. he was looking and listening.