1890.] NEW YORK ACADEMY OF SCIENCES. 117 



silex ill the form of browu flint and chalcedony. Loose sand lies 

 only in hollows between hillocks, the tops of which are wind- 

 blown and bare. On the surface at certain points lie fragments 

 of fossil wood, and rarely half-buried trunks of the same ; it is 

 dignified by the name '^Petrified Forest." Some of this fossil 

 wood proves to be good phonolite. (Specimen exhibited.) 



I noticed here again evidences of water-courses, recent mud- 

 flakes, etc. At the time of my visit the customary strong cool 

 breeze prevailed, and the temperature was 74° in the shade at 

 noon (March 8th). 



On February l(3th I visited a wild valley west of Thebes, known 

 as Wadi Bab-el-Molook, celebrated for the numerous and well- 

 preserved Tombs of the Kings, of great interest to archaeologists. 

 My experience and impressions of this arid region, written out 

 on the spot, were as follows: — 



Passing from the river bank through green cultivated fields 

 of the Nile basin, the sterile, gravelly desert begins abruptly, 

 the sudden transition being determined by the irrigating canals 

 and channels. At the mouth of the valley, about two miles from 

 the Nile, the scene is one of utter desolation ; absolutely no 

 vegetation of any description is visible, not a dry lichen nor a 

 gray shrub. Beneath the feet is a hard gravelly floor, grayish- 

 white in color, consisting of broken and powdered limestone from 

 the neigliborliood, intermingled with nodules and pebbles of 

 silex. True flint, from white to liver-brown in color, and 

 having characteristic conchoidal fracture, is abundant. The 

 silex commonly takes the concretionary form, some of the shell- 

 like an<l ring-shaped masses reminding one of fossils. But little 

 sand is present. 



At the entrance of the valley the hills rise at a gentle slope, 

 their sides being here and there dotted with large masses of 

 limestone with a firm cement, or rather with seams, of dark- 

 colored quartz. The strata, as seen by the unaided eye, appear 

 to be horizontal. The rock has ashaly character in places, being 

 deeply weather-eaten, friable, and soft. Ascending the valley, a 

 spur divides it into two converging ravines; following the longer 

 one to the west, the walls of limestone become precipitous, the 

 quartzitic masses larger, and the general aspect wilder. At 

 some places the limestone runs into chalk; this is especially well 

 seen on entering one of the numerous Tombs of the Kings, the 

 inclined passages penetrating hundreds of feet into the heart of 

 the mountains. 



The valley terminates in a cul-de-sac, about half a mile from 

 its mouth, forming an amphitheatre of nearly vertical walls 

 a])parent]y 200 feet high, above which rise steep slopes i)ei'liaps 



