Some trilobite resting and crawling traces

An attempt is made to explain the formation of smooth trilobite resting traces (Rusophycus) and some features associated with crawling and digging trails Cruziana. Smooth resting traces are frequently current orientated, and it is thought that the scouring action of water currents was largely responsible for their formation. In Cruziana the V-shaped herringbone pattern points in an opposit direction to that of the line of movement. Sets of scratches which make up this pattern explain some aspects of appendage movement.