1899] GREAT GLACIAL MORAINE OF PERMIAN AGE 201 



appearance as seen at different places. It has been described (1) as 

 a rock of igneous origin (" claystone-porphyry ") ; (2) as being a 

 glacier-formed boulder-clay or moraine ; (3) as a breccia composed of 

 angular fragments of volcanic rocks (" trap-breccia ") ; (4) as having 

 been a long line of beach, consisting of blocks, boulders, pebbles, and 

 sand, with volcanic dust and ashes, on the margin of a wide shallow 

 inland sea or lake, disturbed by subaqueous volcanic eruptions ; (5) 

 and lately Dr. G. A. F. Molengraaf, State Geologist, examining this 

 peculiar formation in Zululand, finds evidence that it is really to be 

 regarded as the modified boulder-clay and the moraine of an enormous 

 sheet of land-ice, possibly part of the Antarctic ice-cap of former 

 times ; also that, as with other moraines, during the slow retreat of 

 its ice-field, the water draining from it carried away and spread out 

 the pebbles, sand, and mud separated from its coarser materials. 

 These formed special deposits in river-reaches, lakes, and marshes, over 

 a wide area northward of the hollow curve of its line of retreat. This 

 outspread of the morainic material is recognised as the " Ecca Beds," 

 lying parallel with the moraine (Dwyka Conglomerate), all across the 

 Cape Colony and up through Natal and Zululand. Mr. G. W. Stow's 

 " Olive Shales," associated with the " Boulder-drift " of Backhouse and 

 Douglas, north-west of the Hopetown district, come into the same 

 category. 



In geological position the Dwyka Conglomerate lies directly upon 

 the Carboniferous quartzite of the Wittebergen and the Zuurbergen, 

 and beneath the Ecca beds, which indeed are interlaced with it at 

 some parts of its range, and pass up into the Karoo beds of Mesozoic 

 age. Hence the glacial conditions, originating the conglomerate or 

 moraine, must have been either in the latest Palaeozoic (Permian) or 

 the earliest Mesozoic times. 



How far those ancient glaciers reached northward beyond the 

 present curved morainic border — that is, to what extent glaciers may 

 have occupied the broad hollow, delimited by Palaeozoic rocks, and in 

 which now lie the Ecca and superincumbent Karoo beds, with their 

 concomitant igneous rocks, constituting so large a portion of South 

 Africa — is a subject full of interest. 



The long curvature of this ancient moraine may be likened to 

 some of the sinuosities of the irregular line of great moraines crossing 

 North America, and due to the glaciers of the Arctic ice-fields during 

 the relatively modern Glacial Period, often alluded to by geologists 

 as the " Great Ice Age " of Quaternary times. 



The mountainous land at the Cape can be only a mere remnant 

 of the high lands once reaching southward to the Arctic Circle, and 

 far beyond it, if continuous with the existing visible polar lands, which 

 are about 30 degrees south of the Cape. (See G. W. Stow's remarks on 

 this continent, Quart. Joum. Geol. Soc, 1871, vol. xxvii. p. 54G, etc.) 



Whether a perfect polar ice-cap or partial ice-fields originated the 



