 The American army then began to descend the St. Lawrence.Although Chauncey was supposed to blockade the British in Kingston and prevent them interfering, an effective blockade was difficult in the foul weather of late autumn, and amidst the many islets at the head of the river.This allowed Mulcaster's vessels to return to Kingston to embark a detachment of troops under Lieutenant Colonel Joseph Wanton Morrison and pursue the Americans down the river.