580 PEOP. J. W. GKEGORY ON [NOV. I9II, 



Pleistocene. The surface of the platform is strewn with so many 

 palaeolithic chert-implements, that it was probably the site of an 

 ancient camp. 



The stratigraphical relations of the Derna Limestone are shown 

 by a section across the face of the plateau, about 5 miles south-east 

 of the town, from an ancient megalithic ruin known as Gasr el 

 Harib to the wells at Bint. The ruin stands at the height of 

 750 feet near the northern edge of the plateau, which extends far 

 southwards, to the foot of the hills of Gebel Feteha. The northern 

 face of the plateau shows a good section, illustrated by fig. 1 (p. 579). 

 The lower part of the main scarp, up to the height of about 

 200 feet above sea-level, consists of the cream-coloured Derna 

 Limestone : this is overlain, at the height of 340 feet above sea- 

 level, by a sandy foraminiferal limestone, from which Mr. Chap- 

 man has identified fourteen species of foraminifera, including 

 Nummulites curvispira and Operculina libyca. 



Above this foraminiferal bed follow 60 feet of the brown- 

 weathering, well-bedded limestones ; they end above in a hard 

 rock containing reef-building corals. This coral limestone forms a 

 shoulder on the scarp, surmounted by a megalithic ruin. Above 

 this point there is a more gradual ascent on to the plateau, up a 

 valley cut through a series of massive rough-weathering limestones, 

 and having on its floor some ancient wells from 30 to 40 feet deep, 

 still used by the Arabs. Upon the plateau are some hills of a soft, 

 marly, friable limestone of a pale buff colour, resembling some layers 

 of the Globigerina Limestone of Malta; it yielded a Schizaster 

 which, although too crushed for certain specific determination, 

 resembles Schizaster ederi, sp. now 



The main sequence in this section is, therefore, from a limestone 

 which is probably Aquitanian, through the Slonta Limestones, down 

 to the Derna Limestones. At the foot of the main scarp is a belt 

 of limestones, one of which, at 200 feet above sea-level, yielded a 

 fossil determined by Mr. Newton as the Priabonian Pecten arcuatus 

 Brocchi, and consequently belonging to a horizon much higher than 

 the rocks level with it in the cliffs on the south. The steep scarp 

 south-east of Derna is, therefore, probably a fault-scarp, and the 

 foot-hills at the coast are composed of the downthrown Slonta 

 Limestones. I had, however, no opportunity of collecting further 

 specimens from this area, or of completing the section to the sea. 



(b) Derna to Cyrene. 



We marched from Derna for about 6 miles westwards along the 

 coast, crossing a belt of shore-deposits and delta-fans, which sloped 

 up from the sea to the foot of the plateau-scarp. Along the lower 

 part of the cliff could be seen the cream-coloured Derna Limestones, 

 capped by the bedded, brown-weathering limestones. In a wadi 

 about 3 miles west of Derna, the limestones on the coastal plain 

 dip 5° northwards. Outcrops of a chalky limestone containing flint 

 nodules occur to the west of a wadi, about 4 miles from Derna, and 



