34 



SCIENCE- GOSSIP. 



taken, as other urgent affairs demanded atten- 

 tion. 



From Klip Drift the next move was to Bank's 

 Ylei, and thence to Paardekraal ; the hills or 

 koppies seen on the road all show by their boulder- 

 strewn sides that their tops at least are formed of 

 dolerite, and, as usual, the soil below them is red, 

 while in the lower ground the white lime is ex- 

 posed. In the bed of the Modder, just above 

 Paardekraal Drift, the shales and flags are seen to 

 have a slight southern dip — the first deviation from 

 the horizontal, or apparently horizontal, yet seen in 

 this line of country. About a mile further up the 

 river there is a considerable exposure of these 

 xocks, which are " muddy " thin-bedded sandstones, 

 having a shaly fracture, with intervening layers of 

 sandy shales ; the whole varying in colour from a 

 light blue-grey to almost black. In some positions 

 were septaria, often of considerable size, while 

 occasional fossilised sand-cracks were seen. On 

 the north bank, just above the Drift, is the 

 Paardeberg, which being translated is " Horse 

 Mountain." This is a mass of dolerite ; all the 

 kojDpies on the south are of the same material, the 

 stratified rocks as far as yet seen being confined to 

 the plain-level, where they have been protected 

 from final denudation by their covering of tra- 

 vertine and the red detrital sandy clay. The only 

 exception to this is a mound opposite the Paarde- 

 berg and south of the river, which on one side 

 shows a protrusion of dolerite, and on the other a 

 layer of what appears like chert, lying horizontally 

 ■on sandstones and shales, whose edges are occa- 

 sionally seen, and covered by similar strata. At the 

 Drift opposite Cronje's Laager a section was ob- 

 served of bluish-slaty shale, the top of which was 

 denuded, and is now covered by travertine, and 

 this again by light -reddish sandy soil ; below the 

 bluish was a dark shale. To the south-east of 

 Cronje's Laager is a hill called in the map Stink- 

 fontein, but by the British troops re-named 

 Kitchener's Kop ; this is a mass of dolerite, on the 

 flanks of which are patches of the debris of chert 

 and sandy shales. 



The appended section is suggested as represent- 

 ing diagraruniatically the structure of the country 

 (fig. 2). The dolerite, being a hard rock, has acted 

 as a protective cap to the softer sandy strata, while 

 at the same time it has disguised those strata by 

 its debris. The source of the travertine is not 

 apparent as yet. The age of the strata is not dis- 

 closed by internal evidence, though from the 

 description of the lithological characters of the 

 Karroo given by Professor Green (') they are pro- 

 bably of that period. 



Marching beyond Kitchener's Kop, we come to 

 Osfontein Farm ; then, after a flank march, to 

 Poplar Grove ; and thence on to Eoodepoort, noting 

 nothing new on the way beyond the large variety 

 of bulbous plants that may be seen on the alluvial 



(1) "Quart. Journal Geol. Society." Xo. 174, pp. 246 and 248. 



flats of the Modder River near these places. In 

 the river bed at Roodepoort is a small waterfall 

 over rocks of dolerite. where it was observed that 

 the spheroidal weathering was more marked in 

 this position than on the hills — a fact since ob- 

 served in every position where this rock has been 

 exposed to water-action. The soil during the 

 march to Roodepoort changed to a light buff sand, 

 25 to 40 feet of which are exposed in the river 

 banks. About six feet above the level of the water- 

 fall mentioned, a narrow layer contained shells of 

 a species of Helix like H. nemoralis and a minute 

 bivalve. In another spot further up the river, in a 

 layer of fine gravel about six feet above the pre- 

 sent river-level, was a small ungulate bone, a speci- 

 men of a bivalve, with broken fragments of a 

 similar shell. In a layer about two feet above this 

 w-as found a species of Vhio. A little further up 

 stream these gravelly layers (sections of small 

 streams ?) had disappeared, but three strings of 

 kunkur were seen, evidently deposited by another 

 stream. In the grounds of a farm-house on the 

 river bank were found fragments of rock lying 

 about, evidently brought to this spot for building 

 purposes. Among these were pieces of a dark lime- 

 stone, showing that somewhere not very far away 

 are limestone rocks. This limestone contained 

 minute concretions which at first sight gave the 

 impression of foraminifera. A fossiliferous rock 

 would add to the interest of a region apparently 

 barren of evidence of former life. 



The next march was past Abraham's Kraal, halt- 

 ing at Dreifontein, the soil being again red, with 

 occasional exjtosures of travertine, the koppies 

 boulder-strewn with dolerite as before. The next 

 day saw the column near Kaal Spruit, from which 

 spot the distant hills occasionally showed alter- 

 nating layers of hard and soft rock, this becoming 

 more evident the following day from Venter's 

 Yallei, though it was not possible to approach 

 near enough to identify the rocks. The stones of 

 which a farmer's hut at this locality was built 

 showed several varieties of sandstones, exhibiting 

 bedding streaks, but evidently hewn from thicker 

 strata than any seen previously on this line of 

 march. Continuing onwards, the next day the 

 column bivouacked on a mass of dolerite called 

 Brand's Kop, the following morning marching into 

 Bloemfontein, the country on that side of the Kop 

 being a grass-covered slope towards the town. 



The source of the travertine ( 2 ) forms to the new- 

 comer a subject for speculation, as no rock was 



(2j In the vicinity of Modder River Station, a spot not m- 

 cluaed in these notes, this travertine was observed interbedded 

 thinly and unevenly with a fine gravel, the main bed of which 

 lay beneath the lime ; in another locality near this was a sand- 

 stone, the upper part of which was interbedded with the traver- 

 tine. At Osfontein, where the travertine lay on a denuded 

 surface of shales, fragments of the shales were imbedded in its 

 lower part, forming a breccia ; the same condition was noticed 

 elsewhere, but at this place there was a good section visible in 

 the side of a sluit (a narrow water-channel) cut by man to con- 

 duct water from a spring. 



