sent out flankers again, who succeeded in trapping some militia from behind and inflicting casualties. British casualties were also mounting from these engagements and from persistent long-range fire from the militiamen, and the exhausted British were running out of ammunition. When the British column neared the boundary between Lincoln and Lexington, it encountered another ambush from a hill overlooking the road, set by Captain John Parker's Lexington militiamen, including some of them bandaged up from the encounter in Lexington earlier in the day. At this point, Lt. Col. Smith was wounded in the thigh and knocked from his horse. Major John Pitcairn assumed effective command of the column and sent light infantry companies up the hill to clear the militia forces. The light infantry cleared two additional hills as the column continued east—"The Bluff" and "Fiske Hill"— and took still more casualties from ambushes set by fresh militia companies joining the battle. In one of the musket volleys from the colonial soldiers, Major Pitcairn's horse bolted in fright, throwing Pitcairn to the ground and injuring his arm. Now both principal leaders of the expedition were injured or unhorsed, and their men were tired, thirsty, and exhausting their ammunition. A few surrendered or were captured; some now broke formation and ran forward toward Lexington. In the words of one British officer, "we began to run rather than retreat in order. ... We attempted to stop the men and form them two deep, but to no purpose, the confusion increased rather than lessened. ... the officers got to the front and presented their bayonets, and told the men if they advanced they should die. Upon this, they began to form up under heavy fire." Only one British officer remained uninjured among the three companies at the head of the British column as it approached Lexington Center. He understood the column's perilous situation: "There were very few men had any ammunition left, and so fatigued that we could not keep flanking parties out, so that we must soon have laid down our arms, or been picked off by the Rebels at their pleasure—nearer to—and we were not able to keep them off." He then heard cheering further ahead. A full brigade, about 1,000 men with artillery under the command of Earl Percy, had arrived to rescue them. It was about 2:30 p.m., and the British column had now been on the march since