A heavy fog caused a great deal of confusion among the approaching Americans. After a sharp contest, Sullivan's column routed the British pickets. Unseen in the fog, around 120 men of the British 40th Foot barricaded the Chew Mansion. When the American reserve moved forward, Washington made the erroneous decision to launch repeated assaults on the position, all of which failed with heavy casualties. Penetrating several hundred yards beyond the mansion, Sullivan's wing became dispirited, running low on ammunition and hearing cannon fire behind them. As they withdrew, Anthony Wayne's division collided with part of Greene's late-arriving wing in the fog. Mistaking each other for the enemy, they opened fire, and both units retreated. Meanwhile, Greene's left-center column threw back the British right. With Sullivan's column repulsed, the British left outflanked Greene's column. The two militia columns had only succeeded in diverting the attention of the British, and had made no progress before they withdrew.