Many physical aspects of the depositional environment in which some rocks are formed may be reconstructed with the aid of trace fossils such as tracks, trails, borings, or other evidences of organism activity. Trace fossils are extremely abundant in sedimentary rocks of all ages, but commonly have not been used by geologists as an aid in paleoecologic interpretation. Water depth, salinity, current action, relative acidity, kinetic energy of the depositional environment, rate of sedimentation, and mode of life of the organisms may be deduced by using trace fossils as an interpretation tool.

Orientation of trace fossils in beds may indicate approximate directions of current action, whereas the type of trace preserved connotes the habitat preferred by the organism. Vagile, benthonic, filter-feeding organisms commonly build nearly vertical burrows; detritus-feeding organisms tend to burrow horizontally. Filter-feeders live in an environment where the current velocity is sufficient to winnow fine particles; detritus-feeders live where fine-grained sediments and finely divided organic matter slowly settle from the water. Delicate tracks and trails preserved in rocks are indicators of a calm environment and slow sedimentation rate, whereas tubes, burrows, and borings are built and preserved in current-activated waters.

In sedimentary rocks that are lacking skeletal or body fossils, trace fossils are valuable aids for use in reconstructing the physical history of the depositional environment.

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