Blockhouse Small 320×222 Medium 640×445 Large 1024×712 Download Tiff Original 2400×1668 | (3.8 MB) Description Fortification constructed of timber, muskets and cann0n fire from within. Keywords blockhouse, Cannon, fort, fortification, musket, timber Galleries Military Fortification Source: Editor in Chief Charles Morris Winston's Cumulative Loose-Leaf Encyclopedia (Philadelphia, PA: The John C. Winston Company, 1918)