An updated Cruziana stratigraphy of Gondwanan Paleozoic sandstones

In the years sins the last review (Seilacher„ 1971), the value of trilobitceburrows to date otherwise barren epicontiental sandstone seguences has been corroborated and extended into the Lower Carbenifrous, Newly recognized Cruziana ichnospecies come from now dispersed fragments of Gondwana  (Australia, North Africa, Spain, South America), With this method, the Acacus Sandstone of Sotithern Libya can be shown to be a diachronous unit that prograded northward from Early to Late Silurian times.