the other troops as a rearguard, under Brigadier General John Parker Boyd. Late on 10 November, after a day spent marching under intermittent fire from British gunboats and field guns, Wilkinson set up his headquarters in Cook's Tavern, with Boyd's troops bivouacked in the surrounding woods. British counter-moves The British had been aware of the American concentration at Sackett's Harbor, but for a long time they had believed, with good reason, that their own main naval base at Kingston was the intended target of Wilkinson's force. Major General Francis de Rottenburg, the Lieutenant Governor of Upper Canada, had massed his available troops there. When Mulcaster returned from French Creek late on 5 November with news that the Americans were heading down the Saint Lawrence, de Rottenburg dispatched a Corps of Observation after them, in accordance with orders previously issued by Governor General Sir George Prevost. The corps initially numbered 650 men, and was commanded by Lieutenant Colonel Joseph Wanton Morrison, the commanding officer of the 2nd Battalion, the 89th Regiment. They were embarked in the schooners Beresford and Sir Sydney Smith, accompanied by seven gunboats and several small craft, all commanded by Mulcaster. They departed from Kingston in thick weather late on 7 November and evaded the ships of Commodore Isaac Chauncey, which were blockading the base, among the Thousand Islands at the head of the Saint Lawrence River. On 9 November, they reached Prescott, where the troops disembarked as the schooners could proceed no farther (although Mulcaster continued to accompany them with three gunboats and some batteaux). Morrison was reinforced by a detachment of 240 men from the garrison of Prescott, for a total strength of about 900 men. Marching rapidly, they caught up with Boyd's rearguard on 10 November. That evening they encamped near Crysler's Farm, two miles upstream from the American positions. The terrain was mainly open fields, which gave full scope to British tactics and musketry, while the muddy ground (planted with fall wheat) and the marshy nature of the woods surrounding the farm would hamper the American manoeuvres. Morrison was keen to accept battle here if offered. Battle As dawn broke on 11 November, it was cold and raining, though the rain later eased. Firing broke out in two places. On the river, Mulcaster's gunboats began shooting at the American boats clustered around Cook's Point, while a Mohawk fired a shot at an American party