On the green, between the Whitall house and the river, lies a portion of an iron cannon which burst during the engagement. That event killed several of the Americans. The picture represents its present appearance, with its breech blown away. Beyond it is the Delaware, and in the distance, opposite, is seen Fort Mifflin, lying almost upon the water level on Fort or Great Mud Island, near the western shore. In the far distance, bounding the view, are the hills of Pennsylvania, toward Valley Forge. In the summer of 1777, Sir William Howe, the British commander-in-chief, sailed from New York (a) with a large land force, and with a naval armament under his brother [[ a July 23]] Richard, Earl Howe, and, landing at the head of Chesapeake Bay, (b) commenced [[ b August 25.]] a victorious march toward Philadelphia. Washington, informed of the movement, went out from Philadelphia to meet him, and had proceeded beyond the Brandywine, in the neighborhood of Wilmington, when the van of the enemy appeared at Kennet Square. The battle of Brandywine occurred soon afterward, (a) in which the Americans were [[ a September 11]] defeated, and driven back toward Philadelphia. The enemy pushed steadily forward, and entered the city in triumph. (b) In anticipation of the possibility [[ b September 26.]] of such an event, the Americans had applied themselves diligently to the erection of obstructions in the Delaware, to prevent the ascent of the British fleet, and also in rearing batteries upon the shores to cover them. Upon isolated marshes, or low islands of mud, [[[Military Works on the Delaware.--Obstructions in the River.--Their Removal by the British.--Capture of Billingsport.]]] {292}made green by reeds, a little below the mouth of the Schuylkill, they erected a strong redoubt, with quite extensive outworks, and called it Fort Mifflin. These islands were called Great and Little Mud Islands. The former, on which the redoubt and main works were erected, has been called Fort Island ever since that time. [Illustration: 8302] On the opposite shore of New Jersey, a strong redoubt, called Fort Mercer, was also erected, and well supplied with artillery. In the deep channels of the river between, and under cover of these batteries, they sunk ranges of strong frames, with iron-pointed wooden spikes, called _chevaux de frise_, which formed almost invulnerable _stackadoes_. Three miles further down the river, at Byllinge's Point * (now Billingsport), was a redoubt with extensive outworks, covering strong _stackadoes_, which were sunken there in the navigable channel of the river, between the main and Billing's Island.