Most burrows serve the dual purpose of shelter and a place to feed. Some burrows shelter the bulk of an organism while it reaches out into the water column to feed on suspended particles. Others are complex networks that reveal the organism's ecology. Each burrowing species has a characteristic burrow architecture and many species have preferred depth habitats. Their burrows can therefore help to reconstruct paleodepth.
Tracks are individual imprints left by the passage of an organism over the sediment surface.
Trails are left by organisms that more or less drag themselves across the surface. Resting traces are impressions left where an organism as settled in for some period of time. Some lagoonal, estuarine, lacustrine or tidal flat deposits may be dominated by fecal pellets. The Bahamas Banks is an example of such an area. However it is important to be able to recognize them so that you will not confuse them with primary structures.