<h3>A DANGEROUS VISITOR.</h3>
<p>It was not alone necessary for the plans of Ab and Oak that there should
be made a deep hole in the ground. It was quite as essential for their
purposes that the earth removed should not be visible upon the adjacent
surface. The location of the pit, as has been explained, was some yards
to the northeast of the tree in which the lookout had been made. A few
yards southwest of the tree was a slight declivity and damp hollow, for
from that point the land sloped, in a reed-grown marsh toward the river.
It was decided to throw into this marsh all the excavated soil, and so,
when Ab had outlined the pit and cut up its surface into sods, he carried
them one by one to the bank and cast them down among the reeds where the
water still made little puddles. In time of flood the river spread out
into a lake, reaching even as far as here. The sod removed, there was
exposed a rectangle of black soil, for the earth was of alluvial deposit
and easy of digging. Shellful after shellful of the dirt did Ab carry
from where the pit was to be, trotting patiently back and forth, but the
work was wearisome and there was a great waste of energy. It was Oak who
gave an inspiration.</p>
<p>"We must carry more at a time," he called out. And then he tossed down to
Ab a wolfskin which had been given him by his father as a protection on
cold nights and which he had brought along, tied about his waist, quite
incidentally, for, ordinarily, these boys wore no clothing in warm
weather. Clothing, in the cave time, appertained only to manhood and
womanhood, save in winter. But Oak had brought the skin along because he
had noticed a vast acorn crop upon his way to and from the rendezvous and
had in mind to carry back to his own home cave some of the nuts. The pelt
was now to serve an immediately useful purpose.</p>
<p>Spreading the skin upon the grass beside him, Ab heaped it with the dirt
until there had accumulated as much as he could carry, when, gathering
the corners together, he struggled with the enclosed load manfully to the
bank and spilled it down into the morass. The digging went on rapidly
until Ab, out of breath and tired, threw down the skin and climbed into
the treetop and became the watchman, while Oak assumed his labor. So they
worked alternately in treetop and upon the ground until the sun's rays
shot red and slanting from the west. Wiser than to linger until dusk had
too far deepened were these youngsters of the period. The clamshells were
left in the pit. The lookout above declared nothing in sight, then slid
to the ground and joined his friend, and another dash was made to the
hill and the safety of its treetops. It was in great spirits that the
boys separated to seek their respective homes. They felt that they were
personages of consequence. They had no doubt of the success of the
enterprise in which they had embarked, and the next day found them
together again at an early hour, when the digging was enthusiastically
resumed.
Many a load of dirt was carried on the second day from the pit to the
marsh's edge, and only once did the lookout have occasion to suggest to
his working companion that he had better climb the tree. A movement in
the high grass some hundred yards away had aroused suspicion; some wild
animal had passed, but, whatever it was, it did not approach the clump of
trees and work was resumed at once. When dusk came the moist black soil
found in the pit had all been carried away and the boys had reached, to
their intense disgust, a stratum of hard packed gravel. That meant
infinitely more difficult work for them and the use of some new utensil.</p>
<p>There was nothing daunting in the new problem. When it came to the mere
matter of securing a tool for digging the hard gravel, both Ab and Oak
were easily at home. The cave dwellers, haunting the river side for
centuries, had learned how to deal with gravel, and when Ab returned to
the scene the next day he brought with him a sturdy oaken stave some six
feet in length, sharpened to a point and hardened in the fire until it
was almost iron-like in its quality. Plunged into the gravel as far as
the force of a blow could drive it, and pulled backward with the leverage
obtained, the gravel was loosened and pried upward either in masses which
could be lifted out entire, or so crumbled that it could be easily dished
out with the clamshell. The work went on more slowly, but not less
steadily nor hopefully than on the days preceding, and, for some time,
was uninterrupted by any striking incident. The boys were becoming
buoyant. They decided that the grassy valley was almost uninfested by
things dangerous. They became reckless sometimes, and would work in the
pit together. As a rule, though, they were cautious--this was an inherent
and necessary quality of a cave being--and it was well for them that it
was so, for when an emergency came only one of them was in the pit, while
the other was aloft in the lookout and alert.</p>
<p>It was about three o'clock one afternoon when Ab, whose turn it chanced
to be, was working valiantly in the pit, while Oak, all eyes, was perched
aloft. Suddenly there came from the treetop a yell which was no boyish
expression of exuberance of spirits. It was something which made Ab leap
from the excavation as he heard it and reach the side of Oak as the
latter came literally tumbling down the bole of the tree of watching.</p>
<p>"Run!" Oak said, and the two darted across the valley and reached the
forest and clambered into safe hiding among the clustering branches.
Then, in the intervals between his gasping breath, Oak managed to again
articulate a word:</p>
<p>"Look!" he said.</p>
<p>Ab looked and, in an instant, realized how wise had been Oak's alarming
cry and how well it was for them that they were so distant from the clump
of trees so near the river. What he saw was that which would have made
the boys' fathers flee as swiftly had they been in their children's
place. Yet what Ab looked upon was only a waving, in sinuous regularity,
of the rushes between the tree clump and the river and the lifting of a
head some ten or fifteen feet above the reed-tops. What had so alarmed
the boys was what would have disturbed a whole tribe of their kinsmen,
even though they had chanced to be assembled, armed to the teeth with
such weapons as they then possessed. What they saw was not of the common.
Very rarely indeed, along the Thames, had occurred such an invasion. The
father of Oak had never seen the thing at all, and the father of Ab had
seen it but once, and that many years before. It was the great serpent of
the seas!</p>
<p>Safely concealed in the branches of a tree overlooking the little valley,
the boys soon recovered their normal breathing capacity and were able to
converse again. Not more than a couple of minutes, at the utmost, had
passed between their departure from their place of labor and their
establishment in this same tree. The creature which had so alarmed them
was still gliding swiftly across the morass between the lowland and the
river. It came forward through the marsh undeviatingly toward the tree
clump, the tall reeds quivering as it passed, but its approach indicated
by no sound or other token of disturbance. The slight bank reached, there
was uplifted a great serpent head, and then, without hesitation, the
monster swept forward to the trees and soon hung dangling from the
branches of the largest one, its great coils twined loosely about trunk
and limb, its head swinging gently back and forth just below the lower
branch. It was a serpent at least sixty feet in length, and two feet or
more in breadth at its huge middle. It was queerly but not brilliantly
spotted, and its head was very nearly that of the anaconda of to-day.
Already the sea-serpent had become amphibious. It had already acquired
the knowledge it has transmitted to the anaconda, that it might leave the
stream, and, from some vantage point upon the shore, find more surely a
victim than in the waters of the sea or river. This monster serpent was
but waiting for the advent of any land animal, save perhaps those so
great as the mammoth or the great elk, or, possibly, even the cave
bear or the cave tiger. The mammoth was, of course, an impossibility,
even to the sea-serpent. The elk, with its size and vast antlers, was, to
put it at the mildest, a perplexing thing to swallow. The rhinoceros was
dangerous, and as for the cave bear and the cave tiger, they were
uncomfortable customers for anything alive. But there were the cattle,
the aurochs and the urus, and the little horses and deer, and wild hog
and a score of other creatures which, in the estimation of the
sea-serpent, were extremely edible. A tidbit to the serpent was a man, but
he did not get one in half a century.</p>
<p>Not long did the boys remain even in a harborage so distant. Each fled
homeward with his story.
<br/>
<br/>
<br/></p>
<h2><SPAN name="vii">CHAPTER VII.</SPAN></h2>
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