Brown crystalline limestone with calcite cavities near base 24 -- _Base._ 45 Below come the clays and sandstones of the lowest series, No. 7. In the section above, the limestones are usually too crystalline to show any traces of organic remains, although numerous casts of shells occur at certain points. The calcareous grit, a very well-marked bed, has been observed at points widely distant within the oasis; in places it is a true bone-bed,[46] often highly siliceous and passing into a hard quartzite. Its occurrence here, at the top of the Cenomanian series and below the White Chalk (to be described later) is of great interest, as its position shows it to be probably homotaxial with the bone-beds of Dakhla Oasis[47] and the Eastern Desert,[48] where they are of Campanian age. The bone-beds on this horizon must thus have been deposited over an enormous area. If followed round from the south end of the oasis along the east scarp, the beds of this division are found to gradually become more and more calcareous, consisting often almost entirely of limestone,[49] and to dip more and more to the south-east, till in the neighbourhood of the large sandstone-hill near the scarp in latitude 28° 5′, where the tilting reaches its maximum, they dip at 45° and partly disappear under the sandy covering of the ground between the hill and the scarp. Further north the dip grows less and the beds re-appear, forming the top of the main scarp at the oasis-edge. The organic remains in Division 6 include ammonites, echinids, with _Ostrea_, _Exogyra_ and masses of _Serpulæ_; fossil wood and fragments of bone also occur. These fossils are in places abundant, some bands being almost entirely formed of the shells of _Exogyra_. The ammonites, although apparently specifically identical with those of the lower series, attain a much greater size. The assemblage of forms and the prevalence of bands of limestone point to deeper water conditions than the foregoing underlying series. The following is a list of forms obtained as far as determined:— _Rhabdocidaris_, probably nov. sp. _Diplopodia marticensis_. _Heterodiadema libycum_. _Toxaster radula_. _Hemiaster lusitanicus_ (_roachensis?_) _Serpula_ (_Galeolaria_) _filiformis_.