62 
TWO FINDS ON MOUNT KENIA 
derived from much more extensive icefields above, and swelling 
in the day time as the tropical sun increased their discharge, 
and contracting in volume as the cold of evening came on. 
This process may daily be seen in operation in the small streams 
which are now delivered from the glaciers. Equally, they 
might have been formed on the shores of a lake basin, so 
situated as to fill up more rapidly during the day than the 
water could escape from the discharge outlet. At night as the 
supply ceased, the continuous discharge from the exit might 
lower the level which the water had reached during the day. 
Under either of these suppositions there would occur the rise 
and ebb of wind-swept water over a soft shore, which would 
result in the formation of ordinary ‘ sea-shore ripples.’ Then, 
bursting through the ice w T orld above this desolate sheet of 
water, came another discharge of ash, forming, in the lake- 
shore ripples, the 4 cast,’ which is now left exposed to view. 1 2 
Later in the mountain’s history came other lava flows covering 
stream bed or lake basm under floods of molten rock. For the 
present, at any rate, volcanic activity is not in evidence, and the 
never-ceasing trickle from the glaciers, supplemented by the 
violent rain storms that occur on the mountain, 3 has worn 
through the overlying lava cap, through the bed of ash, and far 
into the underlying masses of rock, with the result that the 
ripple marks are now some 200 feet above the noisy stream 
which cascades along the valley bottom below. 
The head of the valley, as one approaches it, is closed by 
the bold mass of Point Piggott, so named by Professor J. W. 
Gregory 3 after Mr. J. R. W. Piggott, administrator of the 
Imperial British East Africa Company. Passing to the north 
of this mountain, the valley ends in a corrie into which deliver 
the two small glaciers named after Mr. Mackinder’s guides. 
Passing the Cesar glacier (see Illustration No. 2), and the 
little tarn that lies at its foot, one arrives at last at the moraine 
that lies just below the Joseph glacier at an altitude of about 
1 One of the ‘ ripples ’ from this cast was chipped out and has been 
placed in the Society’s Museum. 
2 The writer’s rain-gauge measured a fall of 1*66 inches in fifty minutes 
on the North-East side of the mountain on April 20, 1908. 
3 See ‘ The Great Rift Valley,’ page 173, by J. W. Gregory, D.Sc., &c. 
(21s. John Murray, 1896.) 
