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species is Nurnmulites (Pa- 

 ronia) curvispira Menegh. 1 



Old rock-dwellings have 

 been excavated in this 

 rock, which extends up the 

 wadi as far as we could 

 see. It includes layers of 

 broken shell -fragments 

 and echinoid spines, and 

 some layers, as at Seghia, 

 of pinkish limestone full of 

 N. curvispira and iV. ehren- 

 bergi, 2 inches in diameter. 

 This cream-coloured lime- 

 stone and its associated 

 beds ,whi ch m ay be grouped 

 together as the Derna 

 Limestone, are some 250 

 feet thick. This series is 

 covered by harder lime- 

 stones, which weather 

 brown and are more con- 

 spicuously stratified. They 

 are over 200 feet thick 

 at Derna, and from their 

 great development at 

 Slonta are subsequently 

 referred to as the Slonta 

 Limestones. 



About 6 miles from 

 Derna the wadi divides at 

 the springs of Bonman- 

 sur ; a platform composed 

 of 20 feet of calcareous 

 sands and gravels, inter- 

 bedded with layers of 

 travertine from 1 to 3 feet 

 thick, separates the two 

 branches of the valley. 

 The face of this platform 

 is covered by a sheet of 

 calcareous tufa with many 

 fantastic projections. The 

 sands contain shells, which 

 have been identified by 

 Mr. E. B. Newton as Hy- 

 gromia sordulenta (More- 

 let), showing the age to be 



1 In the following pages 

 any foraminifera the species of 

 which are mentioned have been 

 determined by Mr. Chapman, 

 and similarly the mollusca by 

 Mr. E. B. Newton. 



