The uppermost storey of a tower mill is called the Cap. The Cap is a wooden structure that contains the Wallower, Windshaft and Brake Wheel to which the Sails are connected. The cap can be rotated through 360 degrees to enable the Sails to be pointed into the wind. This is aided in this mill by a ring of Wheels that are set into the base of the cap.
At the rear of the cap is a small external deck called the Tail. It is from here that miller could Rotate the Cap into the wind.
Many mills in Oxfordshire shared the distinctive domed cap with a rear dormer and a round Finial at the peak. The cap was originally covered in copper.