Reviews—Effects of Drought in the Waterberg. 129 
ViI.—Errects oF Drovucut IN THE WaTERBERG, TraNsvAaL.—The 
Smithsonian Report for 1914 has reprinted from the Agricultural 
Journal of South Africa a paper by E. N. Marais on the effects of 
drought in the Waterberg, which has converted over 4,000 square 
miles of the Northern Transvaal, an area equal in extent to the 
‘Orange Free State, once rich in orange groves, and formerly ‘a sort 
of lotus land of fertility, literally overflowing with milk and honey ”’ 
into an absolute desert ‘‘in which there is no single drop of water 
running or stagnant above the surface of the ground’’. He says the 
Limpopo River is now dry throughout this district, and water can 
only be obtained from it by deep sinking in its bed. All the ordinary 
‘springs are empty, and it is only the thermal springs which are still 
flowing; they show no change in volume, though the loss of their 
water between the spring and the dam is 60 per cent greater than 
formerly. The animals have changed their habits or been extermi- 
mated; the vegetation is dead, and most of it has disappeared. The 
author refers to the hope that this extreme drought may mark the 
greatest swing of the pendulum towards desiccation and may be 
followed by improvement; but he remarks that every fact observed 
indicates that the change is permanent, and ‘‘ that the oscillations of 
the pendulum are gradually lessening round the dead point”. He 
regards this desiccation of the Northern Transvaal as part of a climatic 
change, which in the last fifty years has turned thousands of square 
miles of once fertile territory in Asia into desert. Mr. Marais’ 
descriptions are more graphic than convincing. His statement as to 
the habits of baboons’ are either exaggerated or refer to a local 
peculiarity ; and it is difficult to take many of the author’s statements 
seriously, as when he warns us that on the drying up of Lake Rudolf, 
“that most perfect diadem in the girdle of the globe . largely 
depends the fate of the Nile and of fertile Egypt.” Lake Rudolf 
contributes no more water to the Nile than it does to the Mississippi, 
and as the author’s African geography is so imperfect his conclusions 
on Asiatic climate do not carry weight. 
VII.—Crimate oF Grotogic Trme.—Professor Schuchert’s ‘‘ Climate 
ot Geologic Time”’ has been reprinted from Huntington’s Climatic 
Factor (1914, pp. 265-89) in revised form in the Smithsonian report 
for 1914, pp. 277-311. The paper is a valuable summary of the 
chief factors as to the past variations in climate. There are no 
references, but as the authors’ names are quoted the authorities can 
be easily traced. The literature on the subject is so scattered that 
some is omitted, and the knowledge displayed from different parts of 
the world is unequal, but probably no geologist, even though specially 
interested in this question, can read the paper without finding much 
fresh. information. The author insists that the South Australian 
Boulder-clays are pre-Cambrian instead of Cambrian, and accordingly 
holds that there is no evidence of refrigeration of climate i in Cambrian 
times. He accepts the view that ‘‘ the typical glaciation ”, including 
perfect roches moutonnées and thousands of perched blocks in Western 
Ross and Sutherland are due to a pre-Cambrian and not to the 
DECADE VI.—VOL. Il.—NO. III. 9 
