On Wednesday, September 30, 1778, Lieutenant Colonel Butler marched at 3 a.m. with about 350 men on foot and horseback along the heights between Dobbs Ferry and the Saw Mill River into the vicinity of what is now Edgar's Lane and Zinsser Park to counter Hessian patrols. He positioned Major Henry Lee's dragoons and Major Benjamin Ledyard's infantry and arranged an ambush in three places, front, center, and rear, with Continental soldiers concealed behind bushes, rocks, and stone heaps near the road. Meanwhile, Hessian Captain Karl Moritz von Donop proceeded north from Yonkers after Captain Johann Ewald, who had scouted the area earlier that morning, reported no sign of the enemy but warned him to cover his rear and flanks and send only a few men past the narrow defile up to the heights of Post's plantation. Von Donop ignored the warning and allowed Lieutenant Alexander Bickell and 30 infantry to cross the defile, leaving them exposed. Shots rang out as Bickell was attacked by Ledyard's men, and Lieutenant Mertz with his mounted Jägers rushed forward from the rear to relieve him. When the Hessians came within hail, Butler rose from concealment, called on them to come to him, then ordered his regiment to rise from ambush and fire. Major Lee's corps then cut in on the road behind Mertz and separated his mounted Jägers from von Donop's larger force in the rear. Mertz tried to cut through the Continental force but was surrounded, fought until his horse fell and his saber broke, and was captured; every soldier in his company was killed or wounded. Hessian accounts said Bickell's foot Jägers fled into the woods toward the Saw Mill River, while historian Robert Bolton later claimed that soldiers tried to escape toward the Hudson River. Captain Ewald later called the site a small-scale battlefield more horrible than any he had seen. Contemporary accounts conflicted on casualties, but at least 16 Hessians were killed, with more wounded or taken prisoner; the Continentals claimed no losses, though Ewald said the Americans admitted one death. In the rugged terrain of 1770s Westchester, guides were essential to military success, and Isaac "Uck" Odell accompanied Major Butler in the battle.