CH. V. THE OASIS OF SHESHAOUA. 113 



was also a lavender somewhat intermediate in appearance 

 between Lavandula multifida of the Southern Mediter- 

 ranean shores and L. ahrotanoides of the Canary Islands. 

 We also found a form of Cotyledon hispanica of Linnaeus 

 {Pistorinia hispanica of DecandoUe), with pale yellow 

 flowers, intermediate in some respects between the common 

 plant of Southern Spain and P. Salzmanniana of Boissier 

 and Eeuter. 



Resuming our journey, we bore somewhat south of 

 east over a country similar in character to that traversed 

 in the forenoon, but not showing such a complete dead 

 level surface. On the way we noticed for the first time 

 Cucumis Colocynthis, one of the characteristic plants of 

 the desert region, extending from Arabia and Southern 

 Palestine across the entire of Northern Africa, but rarely 

 approaching the littoral zone. Here, as near Suez and 

 elsewhere, so far as we have observed, this plant is curiously 

 infrequent. Growing as it does in a region where it has 

 few rivals to contend with, and the surface is remarkably 

 uniform, one yet finds but one or two individuals scattered 

 at comparatively wide intervals over the stony plain. 

 The fruits are used in Marocco to preserve woollen clothing 

 from moths, but their purgative qualities do not seem to 

 be known to the native doctors. 



Here and there in this part of our route we encountered 

 small blocks of volcanic rock — trap or basalt — as to the 

 origin of which we have no information. We have no 

 grounds for supposing eruptive action to have occurred in 

 this region within a period so recent as that subsequent 

 to the formation of the tufa which covers the whole sur- 

 face of the lower country, and it is not easy to account 

 for the transport of these blocks from a distance after its 

 formation. 



The direct heat of the sun was great in the afternoon, 

 and the way barren and monotonous, so that it was with 

 thorough satisfaction that, on reaching the summit of a 

 slight swelling rise on the plain, at near 5 p.m., we saw 



I 



