 General Carleton arrived in Trois @-@ Rivières late in the action . A detachment of British forces led by Major Grant had taken control of a bridge over the Rivière @-@ du @-@ Loup , a critical crossing for the Americans retreating along the north shore of the Saint Lawrence . Carleton ordered Grant to withdraw , allowing most of the Americans to escape , either because he did not want to deal with large numbers of prisoners or because he wanted to demoralize the Americans further . A significant number of Americans did not make it that far , and were captured . These included General Thompson and seventeen of his officers . It was not until June 13 that the British finished rounding up the stragglers . In all , 236 captives were taken . Brendan Morrissey says that about 30 Americans were killed in the battle , while Howard Peckham gives a figure of 50 Americans killed . 
