The report presents the results of an experimental investigation on the extent of separation of a turbulent boundary layer due to cylindrical protuberances, square prisms, and triangular prisms mounted on a flat plate. The effect of the separated flow on the pressure distribution along the centerline of the plate and on the surface of the attached protuberances is shown. The widths of the protuberances were 0.6 and 1.0 inch, and the ratio of protuberance height to boundary-layer thickness, h/sigma, ranged from 0.3 to 4.4. The test Mach number was 2.17, and the unit Reynolds number was 3,000,000/ft. Results from the experiment indicate that: (1) when h/sigma, the extend of separation is dependent on protuberance height and on the diameter of the cylinder or the breadth of the square prism, but when h/sigma