TRANSACTIONS OF SECTION K. 591 
summer (unless in showers of at least ? inch) may be harmful rather than bene- 
ficial, by inducing the germination of seeds, which are subsequently killed by 
drought. 
With a rainfall such as this agriculture is not possible unless aided by 
artificially applied water. Although at present irrigation works on a large scale 
cannot be attempted, yet along the banks of the Orange River, which runs 
through the area mentioned above, there are pieces of good ground low enough 
to admit of profitable irrigation. At Baviaankrantz, where there is a sheet of 
alluvial soil some thousand acres in extent and G0 feet above the present bed 
of the river, an irrigation farm has been established. When in flood the Orange 
River at this point is 300 yards wide and 50 feet deep, while the quantity of 
silt brought down is so great that if ordinary pep were employed their valves 
and pistons would soon be worn out. This difficulty is overcome by using chain- 
and-bucket pumps, working in shafts sunk at.some distance from the river, The 
shafts are supplied with water by means of a 10-inch syphon, which connects them 
with a rocky pool well out of the main current of the river. 
When raised, the water is distributed by means of 2-foot galvanised steel 
troughing, in which bungholes for drawing off the water are titted every hundred 
ards. 
: The important winter crops are wheat, oats, and other cereals. These require 
altogether some four waterings, the total amount of water used varying with 
situation, season, &c., but a fair average for a cereal crop would be about seven 
hundred tons of water per acre. 
Of summer crops, potatoes form the most important, but peas, beans, and 
many others are grown. ‘These are planted in wet ground, but no more water is 
given till the plants are up, as otherwise a hard cake of soil is formed above them, 
through which the young plants cannot force their way. 
Generally speaking, the great secret of success seems to lie in thoroughly 
breaking up the soil between each watering, and the crops are planted (except in 
the case of cereals, &c.) in such a way as to facilitate this, 
JOHANNESBURG. 
TUESDAY, AUGUST 29. 
The President delivered his Address (see p. 562), after which the following 
Papers were read :— 
1. The Fossil Floras of South Africa. By A. OC. Sewarp, M.A., F.R.S. 
The author gave a general account of the composition of the floras characteristic 
of the Lower Karroo, Stormberg, and Uitenhage series. He referred more 
especially to the desirability of searching for petrified specimens for the purpose of 
microscopical examination, and of obtaining fertile examples of many of the genera 
already described. The paper was read primarily for the purpose of drawing 
attention to gaps in our knowledge and to the chief desiderata from the point of 
view of those interested in the subject of palzeo-botany.' 
2. Recent Information concerning South African Ferns and their 
Distribution. By T. R. Sim. 
) For a detailed account of Fossil Floras of South Africa and for a list of literature 
see Annals of the South African, Museum, vol. iv. 1903. 
