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. "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. 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.