This can be deduced from the pellet-like ornamentation along the tunnel walls, which may have been faecal material (droppings) from the animal living there, or possibly lumps of sand grains. Often Ophiomorpha tunnels become infilled and eroded, as described above for Thalassinoides. This would result in an isolated 'cast' of the tunnel network that could be transported and redeposited somewhere else.