676 MB. G. V. SCOTT ELLIOT AND DR. J. W. GREGORY [Nov. 1 89 5, 



time occupied by glaciers. The following evidence may perhaps be 

 considered as supporting this view : — 



1. Koches moutonnees of the typical rounded kind are common 

 in the Mubuku valley ; but, especially in the Nyamwamba valley, 

 one sees occasionally enormous rounded boulders 10 feet high. 



2. These three valleys are the only ones that I saw which led 

 directly to the snow-peaks. 



3. The accumulations of stones and gravel in both the Nyam- 

 wamba and Mubuku valleys. These are made up of large stones 

 frequently 4 feet in diameter, and sometimes they form, as for 

 example at the mouth of the Mubuku and Sebwe rivers, banks 

 30 feet above the present height of the river. 



I did not at the time realize the importance of this question, and 

 possibly the evidence is not satisfactory ; a height of about 5000 

 feet would be nearly that of the flat valley- bottoms of the Mubuku 

 and Nyamwamba valleys, and this would also be that of the rounded 

 part of the Butagu valley, though in this latter case the present 

 level of the stream is very much lower, as it has cut a deep and 

 narrow channel for itself. 



The quantity of snow on Ruwenzori is at present so small that 

 it seems unlikely that so great an amount of erosion could have been 

 produced ; but, taking into account the length of the snow-ridge 

 and the higher altitude of the mountain in former times, it seems 

 to me highly probable that glaciers did once extend 'down to this 

 level. 



This conclusion was announced in a letter to 'Nature,' Jan. 17th, 

 1895 (vol. li. p. 271), in which the belief was expressed that 

 ' glaciers must have extended 7 to 8 miles down two of the valleys.' 

 It should also be remembered that Stuhlmann ' quotes Emin and 

 Casati as having come to the conclusion that glaciation occurred in 

 this district, the latter even claiming to have found stria?. Stuhl- 

 mann, however, was himself unable to confirm these conclusions. 



IV. The Geology of the Country around Euwenzori. 

 (1) The Archaean Series. 



Leaving Ruwenzori for the surrounding country, we find that 

 this consists of rocks which may be conveniently grouped into two 

 series, one composed of gneisses and schists, and the other of non- 

 foliated sediments. The former are of the type that has an 

 enormous extension in Equatorial Africa, and forms the main plateau 

 on which all the sediments and volcanic rocks have been deposited. 

 On the march from the coast, the rocks of this series are struck a 

 short distance inland from Mombasa, and are crossed through Taita, 

 Tzavo, Kikumbuliu, and the Iveti Mountains to Machako's. There 

 they plunge below volcanic rocks which extend westward to the 

 summit of Mau. The gneisses were known to reappear in Buganda 



1 ' Mit Emin Pasha,' [1893] 1894, p. 298. 



