130 DE. W.F.HUME ON SECULAR OSCILLATION IN EGYPT [Feb. I9TI, 



is typically white chalk throughout, with scattered specimens of 

 Pecten farafrensis (P. mayer-eymari) and Ostrea vesicularis var. 

 judaica in abundance at the base. The Campanian is phosphatic. 

 The best-marked sandstone-bands occur between the Campanian 

 and the Santonian, immediately overlying the Turanian, and at 

 the base of the fossiliferous Cenomanian. The Upper Nubian 

 Sandstone beds have well-marked green and red shales associated 

 with them. 



This series may itself be subdivided into two sub-types : (a) the 

 Hawashian (from Wadi Hawashia), in which ammonites of the 

 Tissotia group are strongly developed in the Turonian strata ; and 

 (6) the Um Hemaiet sub-type, in which ammonites are absent, 

 and the Turonian, as such, is not markedly developed. 



(3) The Hammama type, so named from Wadi Hammama, 

 in which these strata were first recorded by the late Mr. Barron 

 and myself. This type also includes the Campanian strata which 

 had been previously studied by Prof. E. Eraas on the Qena-Qosseir 

 road. The characteristics are : partial replacement of Danian white 

 chalk by the green and red Esna Shales and by Pecten-farafrensis 

 (P. mayer-eymari) Marls, the white limestones forming incon- 

 spicuous bands. The Campanian beds are still phosphatic, but 

 the Turonian and the Cenomanian are no longer represented, the 

 strata of those ages in this position being sandstones, with the ex- 

 ception of the (bituminous) Abu Rahal Lingula Shales. These 

 are at present a local occurrence, for which no parallel has been 

 found elsewhere. 



(4) The Oasis type, in which the Danian shales are rich in 

 corals and small univalves, and the white limestone is characterized 

 by the presence of Echinocorys, Pentacrinus, and a single coral 

 recalling those of the White Chalk in North-Western Europe. As- 

 in No. 3, the Campanian is phosphatic, and the Nubian Sandstone 

 commences immediately below the oyster-beds of that formation. 



(5) The Dungul type, in which the Danian shales are less 

 marked, while the hard subcrystalline limestones contain single 

 corals widely distributed. The Campanian beds are no longer 

 phosphatic, the corresponding strata being very rich in sea-urchins 

 and univalves. The Nubian Sandstone commences immediately 

 below the oyster-zone of this series. 



The varying characters of the above-mentioned five types clearly 

 illustrate the gradual advance of the sea over Egypt during Upper- 

 Cretaceous times, the invasion having commenced earlier in North- 

 Eastern Egypt, and tho transition being marked by the relative- 

 distribution of the sandstones, clays, and limestones, both in time 

 and in space. Among the most interesting features are the faunal 

 enrichment of the Danian limestones in the south-west, probably due- 

 to their deposition in shallower waters ; the change from phosphatic 

 conditions to abundant sea-urchin and univalve life in the same- 

 direction ; the prevalence of limestone in the north, of sandstone^ 

 in the south, and of an alternating series of limestones and 

 sandstones in the centre of Egypt. 



