So, again, how did sea shells end up in the desert?
From YOUR link:
quote:The African Plate comprises several continental blocks or cratons, stable continental blocks of old rocks, which came together to form the African continent during the assembly of the supercontinent Gondwana around 550 million years ago.
quote:The regional stratigraphy is continuous across North Africa and have been controlled by the tectonic history of individual basins. Deformational events in the region, most of them minor, are recorded by unconformities reflecting basin tilting, uplift, and erosion of intracratonic structural axes at various throughout the Phanerozoic. The main old deformational events occured in the Precambrium to Early Cambrium, Late Silurian to Early Devonian, Carboniferous to Permian.