Vol. 67.] THE GEOLOGY OF CYRENAICA. 585 



The limestone at the level of about 900 feet is soft, and has been 

 excavated for cave-dwellings. It passes, apparently gradually, into 

 the hard, brown-weathering limestones ; they form the surface of 

 a wide plateau, which rises slowly inland to the foot of the ujDper or 

 Cyrene Escarpment. At the level of 1100 feet, in the lower part of 

 these limestones, is a layer crowded with scattered echinoid-plates. 

 This lower plateau has a rough, irregular surface with many 

 limestone-hummocks, and small patches of thin soil in the hollows 

 between them. This limestone continues past Ain Hafra, where it 

 yielded the Priabonian Euspira possaguensis Oppenh., and forms 

 the surface of the ' lower plateau ' directly to the north of Cyrene. 

 The section there begins on the north with the Echinoid Limestone 

 at the height of about 1 100 feet ; it underlies a white hard lime- 

 stone, which weathers very irregularly and forms the foundation of 

 the plain covered by sandy alluvium north of Cyrene. At the 

 base of the cliff which leads to the upper plateau is a limestone 

 containing the Middle Eocene echinoid Fibularia luciani and 

 Nummulites Gurvispira ; it crops out at the height of 1215 feet. 

 This rock is succeeded by a shelly limestone containing many 

 nummulites, including N. gizeliensis var. lyelli. The upper part 

 of this '"lyelli 7 limestone yields a few specimens of Echinolampas, 

 one of which was collected from the height of 1320 feet ; and the 

 tombs of the northern necropolis of Cyrenaica have been mostly 

 excavated in the beds of this soft foraminiferal limestone, which are 

 interstratified with the harder bands. 



The limestones used for the tombs are succeeded by a marly 

 limestone, which is full of irregular nodules and many flattened 

 stem-like fragments, and contains grains of glauconite. This bed 

 has an irregular horizontal lamination, which helps to render it 

 relatively impermeable to water sinking downwards through the 

 overlying porous jointed limestone. This layer accordingly throws 

 out a series of springs along the face of the escarpment. The most 

 famous is the ' Fountain of Apollo ' (or Ain Sciahat), at the height of 

 about 1760 feet above sea-level. The limestone above the Fountain 

 of Apollo is massive and contains some reef-corals, and it passes into 

 a soft earthy limestone containing layers of marl and many pectens, 

 identified by Mr. Newton as JEquipecten zitteli Fuchs, JS. cama- 

 retensis (Font.), JE. scabrellus (Lam.), Pecten vezzanensis Oppenh., 

 etc.: the horizon is, therefore, Aquitanian. This Pecten Bed and 

 the limestone above it also yielded some echinoids, including one 

 which, though imperfect by reason of weathering, I had no hesitation 

 in identifying from its characteristic form as Hemiaster scillce. 

 According to this identification, the echinoids agree with the mollusca 

 in demonstrating the Aquitanian age of the Cyrene Limestones. 



The general dip of the rocks in this area is slightly northwards, 

 but occasionally it is reversed, and in the hill-face east of Ain Sciahat 

 is a clear dip of 3° southwards. 



The hills south of Ain Sciahat, between it and the upper 

 part of the wadi of Bil Ghadir, the next wadi to the west, consist 

 of the Cyrene Limestones, with the spring-forming marl at their 



