i6 SOME ACCOUNT OF THE 



to Constantinople three months later, but the cold weather there killed 

 the last of them. 



The mountains are of red porphyry intersected by numerous dykes 

 of trap. This is surely the proper country for a geologist to come to ; no 

 annoying mantles of soil or vegetat'on conceal the rock masses ; all is bare 

 and clear, and a good view reveals as much as a shire full of welUborings 

 and railway-cuttings. 



The temperature became much colder, falling to within five or six 

 degrees of freezing-point at night, and we found it difficult to keep warm 

 enough in our tents. 



Acacia bushes become rare or absent at about 3,500 feet elevation. 

 Acacias may be said to mark the vertical limits of the desert flora, as the 

 date-palm does its horizontal geographical distribution. The desert plants 

 which exceed this range upwards will be found to be mostly Mesopotamian 

 or Syrian species, and not confined to that belt which extends from the 

 Cape Verdes to Scinde. 



In Widy es Sheikh some large tamarisk-bushes {T. nilotica) occur, 

 about 15 feet in height. This plant has about the same upward limit as 

 that of the acacia. On these tamarisks were two butterflies, one of which, 

 Pyrameis cardui, Linn., was obtained ; the other appeared to be a fritillary 

 (Argynnys). 



The Widy es Sheikh is of considerable length, upwards of twenty 

 miles, running east at first, and then south to the base of the Jebel Mtasa 

 group. It lies high, 3,000 to 4,000 feet, and the chief plants in it are 

 Artemisiae, Santolina, and Zilla, except on the northern sides at the base 

 of whatever shelter from the sun there may be. Here most of the plants 

 lately enumerated occurred still. Some appeared which were less common, 

 as Zygophyllum album, Linn. ; Nitraria tridentata, Desf. ; Alhagi 

 maurorum, D. C. ; Crosophora obliqua, Vahl. ; Pancratium Sickembergeri, 

 A. et S. ; and the labiates and composites of Wadies Lebweh and Berah. 

 Gompkocarptis sinaicus, Boiss., often arrested attention, shedding its 

 beautifully silky tufts of hair, ready to whisk the attached seeds about the 

 peninsular plains with every breath that blows. Phagnalon nitidum, 

 Fres. ; Anabasis setifera, Moq. ; and A triplex leucoclada, Boiss., occurred 

 in Widy Solif, so that the Salsolacese only require favourable circum- 

 stances to appear in the upper country. In Widy Solif, a smaller arm 



