314 The American Geologist. May, 18% 
stones and conglomerates. The strata of this formation, 
among which maybe seen primary rocks like the pre-Cambrian. 
Cambrian and Silurian, are generally steeply inclined. 
Eruptive rocks are found there in dykes, cutting the sedi- 
mentary rocks perpendicular to their stratification or in bed- 
ded dykes, generally striking east and west and related in 
either case to the metalliferous deposits. 
The '"Cape formation" and hence that of the Witwatersrand, 
contains at its base ferruginous schists which are a promising 
horizon for further investigations. Above it comes the form- 
ation containing the auriferous quartzytes and conglomerates. 
This formation has generally but a slight dip taken as a 
whole: but on the borders of the folds formed by the strata 
they are seen to have a steep inclination. In the " de Kaap " 
district, according to Mr. Van Geruber, they appear to be but 
little disturbed at their contact with the granite, which tends 
to prove that the granite was there at the time of their depo- 
sition. From fossils found at the Cape these strata are known 
to belong to the lower Devonian. Composed of regular strata of 
sandstone and conglomerate which indicate a shore line, and 
resting on the sharply folded strata of the Swazi formation, 
we are led to the supposition that here, as in Europe, the 
Devonian is deposited at the foot of a Caledonian range. 
The Carboniferous formation is represented by quartzytes 
and thick strata of dolomyte which rest unconformable on 
the Cape formation. According to fossils found at one locality 
by Mr. Draper these dolomytes belong to the lower Carboni- 
ferous. This limestone formation extends over vast areas and 
maintains its uniformity of aspect and horizontal position. 
It has been affected by the intrusion of eruptive rocks and the 
advent of gold and other metals. 
Finally all these formations have been covered unconform- 
ably by the thick and regular strata known under the name 
of "Karoo."" The sandstone formation of the Karoo comprises 
sandstones and variegated schists which contain important 
deposits of combustible materials worked at a large number of 
localities. Extensive erosion has removed this formation over 
large areas; but remnants everywhere remain which testify 
to its former distribution over all of South Africa. From the 
fossils found these strata are recognized as of Permian and 
