A sequence of soft-sediment deformation structures occurs in Late Quaternary sediments near Ottawa, Canada. The sediments are attributed to deposition on subaqueous outwash fans in the Champlain Sea, at the submerged front of the retreating Wisconsin glacier. In upward sequence the deformed units comprise convolute stratification, ball and pillow structures and dish structures. Deformation is attributed to slumping on the subaqueous fans and/or to the melt-out of ice blocks which had been buried by fan sediments. The sequence of structures is interpreted in terms of a series of events. as follows: 1. (1) Local fluidization of low permeability sediments formed convolute stratification; disrupted anticlines acted as vertical diapirs through which fluidized sediment ascended; 2. (2) the diapirs penetrated overlying, more cohesive sediments, forming ball and pillow structures; 3. (3) dish structures formed in silty fine sand which had passed upward through the diapirs and between the ball and pillow structures. In some cases the silty sand moved downslope as a liquefied sediment flow and dish structures were deformed to give oval plan forms with long axes normal to the local paleoslope.