304 Carboniferous Glaciation , Etc .— White. 
longing to the Carboniferous system; and this rests uncon- 
formably on the Silurian slates, and partly conformably on 
richly fossiliferous Devonian beds. 
The series of these freshwater formations in South Africa is 
as follows: The Ecca beds, at the base, consist of three 
members of which the lowest, the Ecca shales, which 
appear only in a few places, are strongly contorted. All 
the other horizons are nearly absolutely horizontal. 
Between the upper and the lower Ecca beds lies the 
Ecca conglomerate, or “ Dwyka conglomerate ” of T. R. 
Jones, which contains the glacial indications first dis¬ 
covered by Sutherland and afterwards described by Dunn 1 
and others. These conglomerates, regarded at first as vol¬ 
canic, consist of a blue clayey material in which fragments of 
granite, gneiss, greenstone and clay slate are imbedded. 
These vary in size from grains of sand to boulders six feet in 
diameter and weighing 6 to 10 tons. “ They are often 
smoothed as if ground down in a clayey sediment, but they 
are not rounded like blocks which have been exposed to sur¬ 
face action.” The fracture of the clayey matrix is not con- 
choidal. A tendency to obscure, wavy bedding has been ob¬ 
served, and traces of ripple marks show distinctly. As a rule 
the contacts of the Ecca boulder-beds and the Table Moun¬ 
tain sandstone are unconformable, the contact surfaces being 
marked generally with scratchings and deep grooves “ as if 
some heavy semi-plastic substance with included hard angu¬ 
lar fragments had moved across it.” These features have 
been noted in many localities. The upper Ecca shales and 
sandstones show a gradual transition from the boulder beds 
and conglomerates. Coal seams occur here in places, with 
fossil wood, saurian, and plant remains; but of the last 
named only the genus Glossopteris has been described. 
Ascending from the Ecca beds, the Karoo beds (proper) are 
met, beginning with the Kimberly conglomerate, and includ¬ 
ing the Koonap, Beaufort and Stormberg beds, and resting un- 
conformably on the Ecca beds. In his paper on the Geology 
of South Africa, 2 T. R. Jones pronounces the Kimberly beds 
1 E. J. Dunn. Report on the Camdeboo and Nieuweldt coal, Cape of 
Good Hope. Cape Town, 1878, 24 pp., 4to. Reviewed by T. R. 
Jones, Geol. Mag., [2] vi, 1879, No 12. 
2 Rept. Brit. Assoc. Adv. Sci., Montreal meeting, 1884. 
