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 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 paleozoic 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 elephant's 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 plesiosauruses, 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 just said is the Latin names of rhinocerosses or hoponthomases or giraffees, 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 if 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 will blaze," answered the other lad, who had picked up an axe and was stepping toward 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.