Sedimentary structures in carbonate micrite sediments of the Green River Formation (Eocene) have been interpreted as breccias, mudflows, turbidites, or fossil soils. After careful study of these sediments and their vertical and lateral associations, they are actually seen to be transposition structures that result from intrastratal viscous or hydroplastic flow.

Some of the features that are associated with the soft-sediment deformation include microfaults, microfolding, flair structures, ball-and-pillow type structures, lense- and tear-shaped intraclasts, lineated intraclasts, unusually shaped intraclasts, "roof-pendant" intraclasts, and "fluidized" sediment.

When deformed units are traced laterally for even small distances (< 1 m) they may grade into undeformed units. Many units form boudinage structures and completely disappear laterally for short distances. Discontinuous "breccias" can be traced laterally or vertically in many instances to intact, undisturbed sedimentary units. Vertical associations are large-scale arcuate or fold structures (wavelengths 3 to 4 m), soft-sediment injection features, and mudcracks up to 2 m deep.

This case study points out the necessity of caution when interpreting carbonate micrite sediments that contain intraclasts that may at first appear diagnostic of primary breccias, mudflows, turbidites, or fossil soils.

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