Spencer's force advanced to a position on the old York road at Hart's corners (Hartsdale, New York) and there exchanged fire with the Hessians led by Colonel Johann Rall that were at the head of the British left column. When Clinton's column threatened their flank, these companies were forced into a retreat across the Bronx River that was initially orderly with pauses to fire from behind stone walls while fire from the troops on Chatterton Hill covered their move, but turned into a rout with the appearance of dragoons. Rall's troops attempted to gain the hill, but were repelled by fire from Haslet's troops and the militia, and retreated to a nearby hilltop on the same side of the river. This concerted defense brought the entire British Army, which was maneuvering as if to attack the entire American line, to a stop.