The firing from the garrison ceased, and the Americans expected every moment to see a white flag displayed from the block-house in token of surrender. Lieutenant Riddle, whose corps had brought up the prisoners taken in the woods, was sent forward with a small party to reconnoitre. General Pike, who had just assisted with his own hands in removing a wounded soldier to a comfortable place, was sitting upon a stump conversing with a huge British sergeant who had been taken prisoner, his staff standing around him. At that moment was felt a sudden tremor of the ground, followed by a tremendous explosion near the British garrison. The enemy, despairing of holding the place, had blown up their powder magazine, situated upon the edge of the water at the mouth of a ravine, near where the buildings of the Great Western Railway now stand. The effect was terrible. Fragments of timber and huge stone of which the magazine walls were built were scattered in every direction over a space of several hundred yards. When the smoke floated away the scene was appalling. Fifty-two Americans lay dead, and one hundred and eighty others were wounded. So badly had the affair been managed that forty of the British also lost their lives by the explosion. General Pike, two of his aids, and the British sergeant were mortally hurt, while Riddle and his party were unhurt, the missiles passing entirely over them. The terrified Americans scattered in dismay, but they were soon rallied by Brigade-Major Hunt and Lieutenant-Colonel Mitchell. The column was re-formed and the general command was assumed by the gallant Pennsylvanian colonel, Cromwell Pearce, of the Sixteenth, the senior officer. After giving three cheers, the troops pressed forward toward the village, and were met by the civil authorities and militia officers with propositions of a capitulation in response to a peremptory demand for surrender made by Colonel Pearce. An arrangement was concluded for an absolute surrender, when, taking advantage of the confusion that succeeded the explosion, and the time intentionally consumed in the capitulation, General Sheaffe and a large portion of his regulars, after destroying the vessels on the stocks, and some storehouses and their contents, stole across the Don, and fled along Dundas Street toward Kingston. When several miles from York they met a portion of the King's Regiment on their way to Fort George. These turned back, covered Sheaffe's retreat, and all reached Kingston in safety. Sheaffe (who was the military successor of Brock) was severely censured for the loss of York. He was soon afterward superseded in command in Upper Canada by Major-General De Rottenburg and retired to Montreal to take command of the troops there.