A day or two later they reached the wonderful Big Bone Lick, and they approached it with the greatest caution, because they were afraid lest an errand similar to theirs might have drawn hostile red men to the great salt spring. But as they curved about the desired goal they saw no Indian sign, and then they went through the marsh to the spring itself.
Henry opened his eyes in amazement. All that the schoolmaster and Paul had told was true, and more. Acres and acres of the marsh lands were fairly littered with bones, and from the mud beneath other and far greater bones had been pulled up and left lying on the ground. Henry stood some of these bones on end, and they were much taller than he. Others he could not lift.
"The mastodon, the mammoth and I know not what," said Mr. Pennypacker in a transport of delight. "Henry, you and Paul are looking upon the remains of animals, millions of years old, killed perhaps in fights with others of their kind, over these very salt springs. There may not be another such place as this in all the world."
Mr. Pennypacker for the first day or two was absolutely of no help in making the salt, because he was far too much excited about the bones and the salt springs themselves.
"I can understand," said Henry, "why the animals should come here after the salt, since they crave salt just as we do, but it seems strange to me that salt water should be running out of the ground here, hundreds of miles from the sea."
"It's the sea itself that's coming up right at our feet," replied the schoolmaster thoughtfully. "Away back yonder, a hundred million years ago perhaps, so far that we can have no real conception of the time, the sea was over all this part of the world. When it receded, or the ground upheaved, vast subterranean reservoirs of salt water were left, and now, when the rain sinks down into these full reservoirs a portion of the salt water is forced to the surface, which makes the salt springs that are scattered over this part of the country. It is a process that is going on continually. At least, that's a plausible theory, and it's as good as any other."
But most of the salt-makers did not bother themselves about causes, and they accepted the giant bones as facts, without curiosity about their origin. Nor did they neglect to put them to use. By sticking them deep in the ground they made tripods of them on which they hung their kettles for boiling the salt water, and of others they devised comfortable seats for themselves. To such modern uses did the mastodon come! But to the schoolmaster and the two boys the bones were an unending source of interest, and in the intervals of labor, which sometimes were pretty long, particularly for Mr. Pennypacker, they were ever prowling in the swamp for a bone bigger than any that they had found before.
But the salt-making progressed rapidly. The kettles were always boiling and sack after sack was filled with the precious commodity. At night wild animals, despite the known presence of strange, new creatures, would come down to the springs, so eager were they for the salt, and the men rarely molested them. Only a deer now and then was shot for food, and Henry and Paul lay awake one night, watching two big bull buffaloes, not fifty yards away, fighting for the best place at a spring.
Ross and Shif'less Sol did not do much of the work at the salt-boiling, but they were continually scouting through the forest, on a labor no less important, watching for raiding war parties who otherwise might fall unsuspected upon the toilers. Henry, as a youth of great promise, was sometimes taken with them on these silent trips through the woods, and the first time he went he felt badly on Paul's account, because his comrade was not chosen also. But when he returned he found that his sympathy was wasted. Paul and the master were deeply absorbed in the task of trying to fit together some of the gigantic bones that is, to re-create the animal to which they thought the bones belonged, and Paul was far happier than he would have been on the scout or the hunt.
The day's work was ended and all the others were sitting around the camp fire, with the dying glow of the setting sun flooding the springs, the marshes and the camp fire, but Paul and the master toiled zealously at the gigantic figure that they had up-reared, supported partly with stakes, and bearing a remote resemblance to some animal that lived a few million years or so ago. The master had tied together some of the bones with withes, and he and Paul were now laboriously trying to fit a section of vertebræ into shape.