Stratigraphic studies in the Ouachita Mountains of Arkansas indicate the presence of a diverse assortment of rocks which have moved by gravity subsequent to initial deposition. A tentative classification of these subaqueous gravity features is proposed which, hopefully, gives a qualitative measure of downslope distance. By plotting thickness, types, and numbers of post-depositional sedimentary structures, a better understanding of basin geometry during deposition will be obtained.

One major deposit resulted from failure of both soft muds and interbedded incompetent sands. Slight downslope movement produced mixed masses of sand with flow structures and squeezed mud which might be pulled into clay "galls." Continued movement possibly caused disintegration of sand blocks to produce sandy mud and pebbly sand, finally becoming subaqueous turbidity flow as viscosity decreased. A second class of disruptive bedding resulted from plastic flow of soft mud only. Some interbedded sand behaved incompetently, failing by folding; the more competent sand eventually was pulled apart to become exotic blocks.

Slight movements generally can be determined by the character of slides, slumps, and contortions of interbedded sand. Longer-distance movement by mass flow produced contorted mud with exotic blocks of all sizes, shapes, and compositions. A third deposit had failure confined to fine-grained sand with high internal clay content. Some beds show minor plastic flow; others are visibly contorted. The downslope beds also would be turbidity-current deposits.

The Ouachita trough possibly consisted of an offsetting series of unstable mud slopes deepening southwest toward Oklahoma, laced with sand-feeder channels opening into laterally migrating submarine fans characterized by massive sand. More lateral or distal deposits generally are rhythmic and contain few second-cycle bedding features.

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