was created by contortions of the earth's crust that caused Cretaceous limestone
El-Hassana Dome was created by contortions of the earth's crust that caused Cretaceous limestone, 135 million years old, to break through younger formations. At el-Hassana, north of Cairo a dome-like structure stands alone in the predominantly Eocene plateau of about 50 million years old. The contortions and folding are quite clearly visible in the dome in which numerous marine fossils are embedded. Despite the aridity of the area, there is some vegetation, as well as lizards and the ubiquitous White-crowned Black Wheatear, Oenanthe leucopyga.