Meanwhile, he had determined to fortify himself for the winter (it was now the middle of January) in a position where he could face an Illinois outbreak, or an Iroquois invasion, better than he could do in the Indian camp where he was then a guest. Taking advantage of a thaw, which temporarily reopened the frozen river, he with Hennepin, in a canoe, sought and soon found the site he had chosen. on a low hill, or knoll, half a league from the camp and about 200 yards from the southern bank. In front of this knoll was a marsh, overflowed at high tide, and on either side a ravine. A ditch was dug behind this knoll, connecting these two ravines, and thus isolating it from the mainland. On each side of the hill, which was nearly square, an embankment was thrown up and its sloping sides were guarded by _chevaux-de-frise_, and a 25-foot palisade surrounded the whole. The buildings within this area were of musket-proof timber. This fort, the first civilized act of occupation in the present State of Illinois, he named Fort Crèvecœur.
“La Salle’s men,” says Parkman, “were for the most part raw hands, knowing nothing of the wilderness, and easily alarmed at its dangers, * * * it was to the last degree difficult to hold men to their duty. Once fairly in the wilderness, completely freed from the sharp restraints of authority in which they had passed their lives, a spirit of lawlessness broke out among them with a violence proportioned to the pressure which had hitherto suppressed it. Discipline had no resources and no guarantee; while these outlaws of the forest, the _courriers des bois_, were always before their eyes, a standing example of unbridled license.” Desertions and disaffections among his followers were, at this time, a heavy burden to La Salle; and he even barely escaped from another attempt to poison him. Finally, however, having apparently placated the Indians of the vicinity, and checked, as he hoped, the disposition to mutiny and desertion among his men, which had been a constant menace to his plans,[14] he built, in an incredibly short time, a vessel of 40 tons’ burden with which to descend the river to the Mississippi. He also sent Hennepin and two others in a canoe to explore the Illinois to its junction with the larger river. He himself, having now given up all hopes of the _Griffin_, began a return to Canada, for needed supplies, in canoes, with four Frenchmen and an Indian hunter, leaving the faithful Tonti, with a dozen or so men to hold the fort and guard the half-finished ship. It was a desperate journey, but he felt that unless the articles lost in the _Griffin_ were replaced without delay, the expedition would be retarded for a full year, and probably utterly foiled by the additional expense which would be incurred for the support of his men. On the way he met the two men whom he had sent back to Michilimackinac in search of the _Griffin_, but they brought him no tidings of her fate, and ordering them to join Tonti at Fort Crèvecœur, he pressed firmly on. He also took occasion to examine the capabilities of the “Starved Rock” upon the Illinois, and sent back word to Tonti to make it a stronghold of defense in case of necessity. His journey occupied sixty-five days of incessant toil, danger, and accidents that rendered it “the most adventurous one ever made by a Frenchman in America;” he himself was the only one of the party who did not break down, either from fatigue or illness, and when Lake Erie was reached, it was his arm alone which ferried their canoe over to the blockhouse at Niagara. They reached Fort Frontenac on the 6th of May, and he pushed on directly to Montreal.