288 A Field Naturalist's Ramble in South Africa. [Sess. 



archaean rocks are the rocks of the Cape system — said to 

 be 10,000 feet in thickness. The Table Mountain series are 

 likely of Lower Devonian age. Above the Cape system comes 

 the Karroo, and the lowest member of it is the Dwyka Con- 

 glomerate, consisting of mud, sand, and pebbles derived from 

 glaciated land to the north of it. It is more than 1000 feet 

 thick, and extends over some thousands of square miles. This 

 shows that glacial conditions prevailed over a large extent of 

 land and for a long time. The Dwyka belongs to late Palaeo- 

 zoic times. The mountain-ranges seem to have been raised 

 between the Dwyka and the Cretaceous times by a thrust 

 from the south. Sheets or outliers of dolerite often form a 

 cap on softer rocks, and so flat kopjes with steep sides are 

 a feature of South African scenery. 



As we crossed the Karroo we saw some scorpions, many 

 ants, and some queer insects. Some 40,000 species of in- 

 sects found in South Africa have been described. We met 

 several flocks of locusts in different places. 



When we were in the Transvaal we paid a visit to the 

 Agricultural Experimental Station. Amongst a number of 

 investigations going on there, two interested us much. The 

 one was a method of growing peach-trees without watering 

 them, by keeping the soil about the trees continually hoed 

 loose : the loose soil hinders evaporation. The other was 

 raising a maize to ripen in three months — that is, to ger- 

 minate in the season when the rains can be depended on, 

 and to ripen before the early frosts which occur in these 

 elevated regions. 



At Heidelberg we saw a dust-storm : a friend there drove 

 us round the environs, and for some time we could not see 

 beyond the heads of the horses. It lasted a couple of hours, 

 — red dust, how it sticks ! 



When we travelled in the trains we found our Colonial 

 fellow-travellers most communicative. There was a great 

 difference of opinion on economic and social questions. One 

 thing they were almost unanimous about was that the late 

 war was a mistake, and the reason sometimes given was 

 almost amusing, — it did not bring the advantages anticipated ! 



We visited gold mines, both worked by Kafirs and by 

 Chinamen. Of course, our visits were all arranged before- 



