Doc. 50. Colonel Geary's despatch.
Darnstown, Md., September 15.--This afternoon, at half-past 3 o'clock, about four hundred and fifty rebels attacked the extreme right of my pickets, about three miles from this place, opposite Pritchard's Mills. The affair was a splendid one, lasting about two hours. The enemy were driven from every house and breast-work  they occupied. Eight or ten of them are said to be killed and a number wounded. Our loss was one killed. Our victory was complete. The troops behaved admirably. Our cannon were indispensable, and rendered good service in the action.
J. W. Geary, Colonel Twenty-eighth Pennsylvania Regiment.