Teichichnus is an ichnogenus with a distinctive form produced by the stacking of thin 'tongues' of sediment

Sediment

Sediment is naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of fluids such as wind, water, or ice, and/or by the force of gravity acting on the particle itself....

, atop one another. They are believed to be fodinichnia

Fodinichnia

Fodinichnia are trace fossils formed by deposit feeders as they excavate the sediment in search of food. They tend to have repeated patterns or spreites , the shape reflecting the systematic feeding strategy used by the organism as it scours the sediment...

, with the organism adopting the habit of retracing the same route through varying heights of the sediment, which would allow it to avoid going over the same area. These 'tongues' are often quite sinuous, reflecting perhaps a more nutrient-poor environment in which the feeding animals had to cover a greater area of sediment, in order to acquire sufficient nourishment.