530 TRANSACTIONS OF SECTION E. 
ferred from Karungu), and the sleeping-sickness camp has also been removed to 
this healthy district, suitable for Europeans. Thence the lecturer marched north- 
west to the Kavirondo gulf at Homa Bay, leaving the Kisii natives at the Riana 
River. Again’ crossing the dissected peneplain of gneiss (with intrusions of 
quartz-porphyry), he entered upon a grassy undulating plain from which conical 
hills of basalt rise abruptly. Between the little trading ports of Homa and 
Kendu he found gypsum deposits, which probably indicate that at the time of 
their formation the Kavirondo gulf. was isolated from the Victoria Nyanza. 
Denudation has been very active around the abrupt basaltic heights of Ruri and 
Homa, especially since the epoch when the lake stood much higher than at 
present.- The lower contours of the surrounding mountains are rounded, whilst 
the upper peaks, which have never been covered by the water, are sharp and 
jagged. An investigation was made of the soda-lake of Simbi, which lies in 
an explosion-crater, and the coastal region west of Kendu was also explored. 
3. The Country North of Lake Albert. By G. W. Grapnam. 
_ 5. River Development in Central Scotland. By H. M. Cape.. 
5d. The Caitons of the Cevennes. By A. H. Garstana. 
The Cajion of the Tarn was almost unknown even to the French traveller 
until 1890, when the publication of M. Martel’s ‘Les Causses de Languedoc,’ 
and, the year following, ‘ Les. Cévennes,’ drew attention to its majestic scenery 
and interesting geological characteristics. Vast areas in the Cevennes consist 
of plateaux or ‘causses’ nowhere less than 2,000 feet high, split up during the 
course of centuries into different blocks by the rivers that gather in the granite 
mountains of Lozére-Aveyron. On the porous surface the vegetation is ill- 
nourished and stunted. ‘While little moisture remains on the surface, the rainfall 
is considerable. It honeycombs its way through the limestone and collects in 
innumerable streams, which leap from the rock into the gorges of the rivers 
and their tributaries. The climate is severe—cold in cloud, shadeless in sun- 
shine. Descend into the gorges and the change is magical, to the gracious 
atmosphere of a southern climate and a region of luxuriant vegetation. 
The Gorge of the Tarn is 38 miles long, and up to four years ago the 
greater part of it had to be traversed by boat. In parts it contracts to-a width 
of less than half a mile between rocks which exceed 1,600 feet in height. The 
valley of the Jonte, a tributary of the Tarn, which joins it at Le Rozier, is, in ~ 
its proportions, little inferior to the Tarn, and in some stretches shows even 
more resemblance to the cafion type. At a height of 1,000 feet above the Jonte, 
in the limestone cliff which overhangs it, is the entrance to the Grotto of 
Dargilan. Though it does not compare in extent with the more famous Grottoes 
of Han, it has the advantage in the beauty and variety of stalactites. Half a 
day’s journey further on, in the highlands from which Mt. Aigonal rises, is the 
abyss and cavern of Bramabian. Returning from Mt. Aigonal to the Tarn Valley 
by the Defile of the Dourbie, on the summit of the Causse Noir, we meet the huge 
collection of limestone rocks called by the natives Montpellier-le-Vieux. It may 
be doubted whether there is a more fantastic example of the effects of atmospheric. 
erosion on friable dolomite in existence. ; 
MONDAY, SEPTEMBER 9. 
The following Papers were read :— 
1. Dew-ponds and Mist-ponds. By Epwarp A. Marri, F.G.S. 
The author in this Paper gave an account of some experiments which he 
made on the Sussex Downs in order to test the truth of the theory that the 
