Quebec was already threatened by a small force under Benedict Arnold. In the year 1761, while General Murray was in military command of the city and district, an engineer officer, acting under his instructions, had marked out a trail along the route from the Atlantic coast, at the mouth of the Kennebec river, to the confluence of the Chaudière with the St. Lawrence over against Quebec. In 1775, when the American colonists determined to invade Canada, Washington decided to send an expedition by this route to co-operate with the main advance by Lake Champlain and the St. Lawrence. The enterprise required a daring, resourceful leader, and the command was given to Arnold. In the middle of September, Arnold embarked with 1,100 men at Newbury port at the mouth of the Merrimac, and sailed for the Kennebec. In the latter days of September he began his march: some 200 batteaux were taken up the Kennebec, carrying arms, ammunition, and supplies; the troops were partly on board the boats, partly kept pace with them on the banks. The expedition followed the course of the Kennebec and its tributary, the Dead River, crossed the height of land, reached the headwaters of the Chaudière in Lake Megantic, and descended the Chaudière to the St. Lawrence. It was a march of much danger and privation, no easy task for a skilled backwoodsman to accomplish, and full of difficulty when it was a case of transporting a small army. All through October and into November the men toiled in the wilderness, boats were lost, provisions were scarce, the sick and ailing were left behind, the rearguard turned back, but eventually Arnold brought two-thirds of his men through, and, with the goodwill and assistance of the Canadians on the southern bank of the St. Lawrence, emerged at Point Levis on the 8th of November, having achieved a memorable exploit in the military history of America. On the 14th he crossed the river by night, landed where Wolfe had landed before his last memorable fight, and, after summoning the city to surrender without effect, retreated to Pointe aux Trembles, nearly twenty miles up the river, to await Montgomery’s arrival. Meanwhile, Carleton passed by and entered Quebec. [Sidenote: Montgomery arrives before Quebec.]