1905-6.] Formation of certain Lakes in the Highlands. 113 
been filled up by detrital matter brought down the slopes by the 
streams. The plain is surrounded by Trias and Lias limestones. 
The gorge at the lower end is eroded in the gneiss, and on the 
slopes we can see beautiful “ roches moutonnees.” At first the 
gneiss resisted better the erosive action of the glacier than the 
limestones, and formed a rock barrier. When the glacier retreated, 
the stream cut its way through the rock barrier, making a V-shaped 
gorge. The glacier increasing again considerably, the ice found its 
way through the gorge scooped out by the stream. The gorge in 
Fig. 3. — Plain of Barberine. 
the gneiss may be due to river erosion during an interglacial 
period. The lake, now filled up, was due to glacial action in the 
softer rocks. 
2. Lake op Yogealle. 
The small lake of Yogealle (see fig. 4) is one of the most beautiful 
examples of a rock basin I have ever seen. It is a corrie lake eroded 
by the hanging glacier out of the soft limestone called “Neocomien,” 
or Lower Cretaceous, the rocky barrier at the end of the loch being 
composed of a hard limestone called “Malm,” or Upper Jurassic. 
The photographs which accompany the present note speak for 
themselves, and show that we have here true rock basins. 
PROC. ROY. SOC. EDIN. — YOL. XXYI. 8 
