So strange and uncanny was the place in which our sledge party thus unexpectedly found themselves that Phil was for exploring it and attempting to determine its true character at once; but practical Serge persuaded him to wait until they had performed their regular evening duties and eaten supper. “After that,” he said, “we can explore all night if we choose.”

So Phil turned his attention to the dogs, which he unharnessed and fed, while Serge prepared supper, and Jalap Coombs gathered a supply of firewood from the bleached timber ends projecting from the bank behind them. He tested each of these before cutting into it to make certain that it was not a bone, quantities of which were mingled with the timber.

The firewood that he thus collected exhibited several puzzling peculiarities. To begin with, it was so very tough and thoroughly lifeless that, as Jalap Coombs remarked, he didn’t know but what bones would cut just as easy. When laid on the fire it was slow to ignite, and finally only smouldered, giving out little light, but yielding a great heat. As Serge said, it made one of the poorest fires to see by and one of the best to cook over that he had ever known.

Although in all their experience they had never enjoyed a more comfortable and thoroughly protected camping-place than this one, the lack of their usual cheerful blaze and their mysterious surroundings created a feeling of depression that caused them to eat supper in unusual silence. At its conclusion Serge picked up a freshly cut bit of the wood, and, holding it in as good a light as he could get, examined it closely.

“I never saw nor heard of any wood like this in all Alaska,” he said at length. “Do you suppose this can be part of a buried forest that grew perhaps thousands of years ago?”

“I believe that’s exactly what it is,” replied Phil. “I expect it was some awfully prehistoric forest that was blown down by a prehistoric cyclone, and got covered with mud somehow, and was just beginning to turn into coal when the ice age set in. Thus it has been preserved in cold storage ever since. It must have grown in one of the ages that one always likes to hear of, but hates to study about—a palæozoic or silurian or post-tertiary, or one of those times. At any rate, I expect it was a tropical forest, for they all were in those days.”

“Then like as not these here is elephants’ bones,” remarked Jalap Coombs. “I were jest thinking as how this one had a look of ivory about it.”

“They may be,” assented Phil, dubiously, “but they must have belonged to pretty huge old elephants; for I don’t believe Jumbo’s bones would look like more than toothpicks alongside some of these. It is more likely that they belonged to hairy mammoths, or mastodons, or megatheriums, or plessiosauruses, or fellows like that.”

“I don’t know as I ever met up with any of them, nor yet heerd tell of ’em,” replied Jalap Coombs, simply, “onless what you’ve jest said is the Latin names of rhinocerosses or hoponthomases or giraffles, of which my old friend Kite Roberson useter speak quite frequent. He allus said consarning ’em, though, that they’d best be let alone, for lions nor yet taggers warn’t a sarcumstance to ’em. Now ef these here bones belonged to any sich critters as them, he sartainly knowed what he were talking about, and I for one are well pleased that they all went dead afore we hove in sight.”

“I don’t know but what I am too,” assented Phil, “for at close range I expect it would be safer to meet one of Mr. Robinson’s taggers. Still, I would like to have seen them from a safe place, like the top of Groton Monument or behind the bars of a bank vault. Where are you going, Serge?”

“Going for some wood that isn’t quite so prehistoric and that will blaze,” answered the other lad, who had picked up an axe and was stepping towards the entrance to the cavern.

“That’s a scheme! Come on, Mr. Coombs. Let’s help him tackle that up-to-date log outside, and see if we can’t get a modern illumination out of it,” suggested Phil.

So they chopped vigorously at the ice-bound drift-log that had induced them to halt at that point, and half an hour later the gloom of their cavern was dispelled by a roaring, snapping, up-to-date blaze. By its cheerful light they examined with intense interest the great fossil bones that, in various stages of preservation, lay scattered about them.

“I should think a whole herd of mammoths must have perished at once,” said Phil. “Probably they were being hunted by some antediluvian Siwash and got bogged in a quicksand. How I wish we could see a whole one! But, great Scott! now we have gone and done it!”

Phil’s final exclamation was caused by a crackling sound overhead. The sloping moss roof had caught fire from the leaping blaze, and for a moment the dismayed spectators of this catastrophe imagined that their snug camping-place was about to be destroyed. They quickly saw, however, that the body of the moss was not burning; it was too thoroughly permeated with ice for that, and that the fire was only flashing over its dry under surface.

As they watched these fitful flames running along the roof and illuminating remote recesses of the cavern, all three suddenly uttered cries of amazement, and each called the attention of the others to the most wonderful sight he had ever seen. Brilliantly lighted and distinctly outlined against the dark background of a clay bank, that held it intact, was a gigantic skeleton complete in every detail, even to a huge tusk that curved outward from a massive skull. For a single minute they gazed in breathless awe. Then the illuminating flame died out, and like a dissolving picture the vast outline slowly faded from view and was lost in the blackness.

“Was that one of ’em?” gasped Jalap Coombs.

“I expect it was,” answered Phil.

“Waal, then, old Kite didn’t make no mistake when he said a tagger warn’t a sarcumstance.”

“It must have been all of twenty feet high,” remarked Serge, reflectively.

For more than an hour they talked of the wonderful sight, and Phil told what he could remember of the gigantic hairy mammoth discovered frozen in a Siberian glacier, and so perfectly preserved that sledge-dogs were fed for weeks on its flesh.

As they talked their fire burned low, and the outside cold creeping stealthily into camp turned their thoughts to fur-lined sleeping-bags. So they slept, and dreamed of prehistoric monsters; while Musky, Luvtuk, Amook, and their comrades restlessly sniffed and gnawed at the ancient bones of this strange encampment, and wondered at finding them so void of flavor.

Glad as our sledge travellers would have been to linger for days and fully explore the mysteries of that great moss-hidden cavern, they dared not take the necessary time. It was already two weeks since they had left the mining camp, winter was waning, and they must leave the river ere spring destroyed its icy highway. So they were off again with the first gray light of morning, and two days later found them at the mouth of the Pelly River, the upper Yukon’s largest tributary, and two hundred and fifteen miles from Forty Mile.

The last half of this distance had been traversed amid scenes of the same stupendous grandeur that attracts thousands of tourists to the Yosemite and Yellowstone. But our travellers only shuddered at its wind-swept silence and terrible loneliness. The latter was increased by the melancholy ruins of old Fort Selkirk, whose three gaunt chimneys still stand, about one mile below the mouth of the Pelly, on the opposite side of the Yukon. That evening in the snug quarters of Harper, the Pelly River trader, who was the last white man they could hope to meet before reaching the coast, they listened to the story of Fort Selkirk.

It was established in 1850 by the Hudson Bay Company, and was their remotest post. So far removed was it from the base of supplies that goods destined for it were two full years in making the journey from London by ship and across the great northern wilderness by river and portage. Previous to that time the Indian trade of the Yukon valley had been monopolized by the Chilkats, wealthiest, most enterprising, and most warlike of Alaskan natives. Securing goods from the Russians at Sitka, they would carry them to their distant villages in canoes, and transport them across the mountains to Yukon head-waters on their backs. There they would be met by the interior Indians, whom they never allowed to visit the coast.

The Chilkats were shrewd enough to reap enormous profits from this trade, and to fully appreciate its value. As soon, therefore, as they learned of the establishment of Fort Selkirk, and realized that it meant the overthrow of their lucrative business, they resorted to the only method of trade competition of which they had any knowledge. They organized a war party, crossed the mountains, descended the Yukon nearly five hundred miles, and wiped Fort Selkirk out of existence, seizing its goods in payment for their trouble.

From the Pelly River trader our travellers gained much valuable information concerning the routes they might pursue and the difficulties they had yet to encounter. They had indeed heard vaguely of the great cañon of the Yukon, through which the mad waters are poured with such fury that they can never freeze, of the rocky Five Fingers that obstruct its channel, the Rink and White Horse rapids, and the turbulent open streams connecting its upper chain of lakes; but until this time they had given these dangers little thought. Now they became real, while some of them, according to the trader, were impassable save by weary détours through dense forests and deep snows that they feared would delay them beyond the time of the river’s breaking up.

“What, then, can we do?” asked Phil.

“I’ll tell you,” replied the trader. “Leave the Yukon at this point, go about fifty miles up the Pelly, and turn to your right into the Fox. Ascend this to its head, cross Fox Lake, Indian Trail Lake, Lost Lake, and three other small lakes. Then go down a creek that empties into the Little Salmon, and a few miles down that river to the Yukon. In this way you will have avoided the Five Fingers and the Rink Rapids, and found good ice all the way. After that keep on up the main river till you pass Lake Le Barge. There again leave the Yukon, this time for good, by the first stream that flows in on your right. It is the Tahkeena, and will lead you to the Chilkat Pass, which is somewhat longer, but no worse than the Chilkoot. Thus you will avoid most of the rough ice, the great cañon, and all the rapids.”

“But we shall surely get lost,” objected Phil.

“Not if you can hire Cree Jim, who lives somewhere up on the Fox River, to go with you, for he is the best guide in the country.”

So the next morning Phil and his companions again set forth, this time up the Pelly River, with all their hopes for safety and a successful termination to their journey centred upon the finding and hiring of Cree Jim, the guide.