92. The Transactions of the South African Philosophical Society 
South-western types. On the Eastern side only two Proteacez (1 Protea 
and 1 Leucadendron) and a few Restiacez, but not a single heath or 
orchid. In their place abounded species of Crassula, Cotyledon, Aloe, 
and Mesembryanthemum, together with many other plants with fleshy or 
leathery leaves, such as we know to be characteristic of the Karroo. 
Although some South-western plants had also advanced to these 
higher slopes, the general character of the vegetation on the two sides 
of the valley shows a difference greater than (e.g.) that between the 
North and South of Germany, and it is highly interesting to learn 
from Mr. Lightfoot that two species of beetles, known to him from 
Namaqualand did occur only east of the railway line, but not on the 
west. To a certain extent the difference can be accounted for by the 
distribution of sun and shade, the North-western slopes being con- 
siderably cooler than the Eastern, but I am not aware of another 
instance where two floral regions so widely different in their elements 
approach each other so closely, and yet do not mix, without the barrier 
of a mountain or ocean between them. 
