SCIENCE- GOSSIP. 



65 



observed which could have supplied such vast 

 quantities of lime along the 120 miles or so 

 traversed during the march recorded above. The 

 type of strata, leaving out the igneous, was, first, 

 shales ; then thin, flaggy sandstones and shales at 

 Waterval Drift ; followed by a preponderance of 

 shales along the Modder River up to Dreifontein ; 

 and. finally, an indication in the hills seen from 

 Venter's Vallei of thick bands of sandstone, com- 

 pared with the previous flaggy rocks, though the 

 shaly strata preponderated. Taking Professor 

 Green's lithological description ( 3 ), these strata may 

 be set down as "Karroo." It is to be regretted 

 that no fossils could be found to verify the dia- 

 gnosis. The manner in which the sandstones 

 become more pronounced at the eastern end of 

 the line would point to an ascent in the geological 

 scale, judged by the same standard, and remember- 

 ing that the country rises slightly from west to 

 east, the strata at the same time being, to all 

 intents and purposes, horizontal, and only disturbed 

 very locally, such disturbance being but once 

 observed, as noted above. 



This fact points to denudation having occurred 

 from east to west, though the cessation of the 

 travertine towards the end of the march, soon 

 after leaving the Modder River, may indicate that 

 the denudation of the lime rock occurred from the 

 north-east. This travertine was deposited after 

 the denudation of the country had progressed to 

 almost recent conditions, for it always lies on a 

 denuded surface of the rock of the lower. land 

 of the locality — we may call it the valley-rock — 

 generally a shale in the district under review ; and 

 as this valley-rock is the lower level of denudation 

 which has progressed downwards from a height 

 that was once considerably above the altitude 

 now reached by the Drakensberg, the deposition of 

 the travertine dates to a period long subsequent to 

 the formation of the highest strata of the country — 

 sufficiently long to allow of the denudation of 

 some 8,000 feet of rock. Professor Green says of 

 the hills in Cape Colony: "They are all of them 

 purely hills carved out by denudation, and they 

 stand as speaking witnesses of what denudation 

 can do, and of the enormous lapse of time dur- 

 ing which it must have been at work in this 

 country" ( 4 ). 



The highest beds, excepting the volcanic, of 

 South Africa appear to correspond to higher Tri- 

 assie beds in Europe. Therefore their period of 

 elevation may be inferred to be fairly remote, and 

 to afford ample time for the denudation which has 

 taken place, but which is now probably proceeding 

 at a comparatively slow pace. 



The red soil, very sandy at the points more 

 remote from the modern centres of its formation, 

 more clayey on the hill slopes, is derived from the 

 weathering of the dolerite ; and as the dykes and 



{'■>> ' Quart. Journal Geol. Society," Xo. 174, pp. 240 and 248. 

 (4) Luc. iit. p. 261. 



sheets of this material are practically omnipresent, 

 the prevailing colouring of the country is red 

 during the dry season. The fall of the rains rapidly 

 causes the growth of herbage, and converts a 

 barren-looking land into green pastures in a few- 

 days. 



11 was mentioned above thai in the centre of the 

 plain-lands was usually to be found a pan. which. 

 as far as can be judged from the character of the 

 narrow stripof country passed through, was seldom 

 in the present day covered with water. These 

 pans represent the denudation of the country, and 

 as seen superficially are composed of whitish sand. 



flfff&vi. 





Fig. 2. Section" of Country near Paardebero. 



1. Dolerite ; 2. Chert ; 3. Sandy sliales ; 4. Thin sandstones : 

 5. Travertine ; 6. Debris of dolerite, red sand, and boulders. 



The section mentioned above in the banks of the 

 Modder River at Roodepoort may perhaps repre- 

 sent what would be seen were a section possible 

 through one of these sandy pans, and. would point 

 to their formation in recent times. It would show 

 sand, sandy mud, fine gravel, irregularly bedded, 

 with recent and modern shells ; it would be inte- 

 resting to get a section through a large dried-up 

 pan like that between Enslin and Ramdam, as the 

 lowest strata might afford some further clue to the 

 geology of the country. In the case of this pan, 

 its site had evidently been cut out of the travertine 

 now on each side of it : how much deeper it had 

 gone it was impossible to ascertain. 



It is wdth diffidence these rough notes are sub- 

 mitted ; they may possibly prove of some interest 

 as referring to a not very frequented part of the 

 Orange River Colony. The difficulties of the occa- 

 sion and want of transport, necessitating even the 

 omission of a camera from a light scale of equip- 

 ment, must be the apology offered for paucity of 

 details and of illustrations. 



Bloemfontein, May, 1900. 



Stoxyhurst College Observatory. — The 

 "Results of Meteorological and Maguetical Obser- 

 vations, with Report and Notes of the Director. 

 1S99," has been sent us by the Rev. W. Sidgreaves, 

 S.J. It contains the results of an immense amount 

 of careful work, not only at Stonyhurst, but also 

 at St. Ignatius College, Malta. 



C2 



