TRANSACTIONS OF SECTION E. 757 



I reached in September. I came down Tanganyika in an Arab dhow, and after- 

 wards crossed the Stevenson Iload and arrived in the Shir(5 Highlands, eventually 

 emerging from the continent at Chiude, the mouth of the Zambesi. 



The earlier part of the journey was over very well known ground, and I shall 

 therefore begin by trying to point out the relative position of Ruwenzori, which 

 was the objective point of the expedition. 



It rises in a very isolated fashion out of an area which is depressed relatively 

 to the Victoria region plateau. The levels of the Albert Edward Nyanza and 

 Semiliki Valley are both lower than that of the Victoria Nyanza, which is the 

 lowest portion of the granite plateau usually called Uganda. 



Ruwenzori is 16,500 feet in height. Dr. Gregory, in a paper to be published 

 in the Journal of the Geological Society, has pointed out grounds for supposing 

 that it is a ' schoU ' mountain. The central core, of which I brought home a speci- 

 men, has been, in a sense, forced through the schists, Avhich I found to dip away 

 from it in all directions. 



It is allowable to suppose that this process resulted in lines of crack or weakness. 

 I found along what may be supposed to be lines of weakness of this kind a series 

 of relatively recent volcanic craters and crater lakes. The most important is that 

 which has produced the division of the Albert Edward into the Nyanza proper and 

 Lake Ruisamba. The Salt Lake and four other craters belong to this line, which 

 is approximately south-east. There is another running south-west, and along the 

 eastern side one finds at least two others ; one, at Vijongo, is in a north-easterly 

 direction, whilst the other is nearly due east from Kyatwa and Butanuka. 



These have all had the most important effect on the geography of the country 

 round the mountain, but this cannot be clearly shown without a large-scale map. 

 The recent volcanic area also extends across the Albert Edward and occupies a 

 stretch of its eastern shore. 



It seems strange that the mountain escaped notice so long, but it is obviously 

 the ' Blue Mountains ' of Sir S. Baker and the ' mountains of Usongora ' which recur 

 frequently in Emin Pasha's letters. 



The reason is probably the way in which it is frequently covered with clouds. 

 At about 10 A.M. thick clouds usually hang at an average level of 7,000 feet to 

 11 ,000 feet, though they are much lower in the narrower valleys. As the morning 

 advances, they gradually ascend, and may vanish altogether at about 5.30 p.m. In 

 fact, before r).30 p.m., or occasionally just about sunrise, it is most unusual to see 

 the summit except from a very great distance. 



The vegetation follows the average movement of this cloud belt. From 5,000 

 to 7,000 feet the surface is covered by shrubs and cultivation. The true mountain 

 forest begins at 7,000 feet, and extends to 8,600 feet. From 8,600 to 10,000 or 

 11,000 feet is a bamboo jungle; and from the latter level to 15,000 feet is a 

 heather zone. 



The forest is very dense, full of creepers, and with occasionally very fine timber. 

 Sometimes it contains tree ferns, and is extremely similar to the wet forests of 

 the Congo. 



Mammal and birds are scarce. Bush buck may be seen occasionally, and there 

 are Cercopit/ipcus n. sp., Colobus, probably a new species, various squirrels, Galago, 

 etc., but all are unusual. Butterflies also are particularly scarce. 



The bamboo region is always extremely cold and wet, and climbing is exces- 

 sively difficult and uncomfortable. 



The ground in the heather region is mainly a wet and soft peat moss. Amongst 

 this are mas.ses of Viola Abyssinica (which I saw visited by a new species of Ar- 

 gynnis, A. Elliotii Butler), Cerastiiim Africanum, Epilohium sp., Cardamine sp., 

 and Hypericum. There are extremely large-fruited kinds of Rubus, and, in the 

 more sheltered ravines, enormous trees of Ericinella Johnstonei, as well as arbores- 

 cent Senecios, Hypcricacece, and the extraordinary tree Lobelia. 



The mountain is in reality a meeting-place of fioras. 



The higher altitude plants are probably of Abyssinian origin, and have a very 

 strong Mediterranean affinity. Those in many of the more humid and wet valleys 

 at from 6,600 to 7,600 feet are of a distinctly Western type, while in the drier 



