SCIENCE- GOSSIP. 



GEOLOGICAL NOTES IN ORANGE RIVER COLONY 

 By Major B. M. Skinner, R.A.M.C. 



1. From Enslin to Bloemfontein. 



A FEW remarks on the geology of the narrow 

 tract of country lying between Enslin and 

 Bloemfontein may perhaps prove of some interest, 

 even though the notes from which they are taken 

 were jotted' down often on stray scraps of paper. 

 The country observed was strictly confined to the 

 line of march, the collection of rock specimens 

 being an impossibility, owing to want of any means 

 of carriage. 



Enslin is on the railway between the Modder and 

 Orange rivers, and consists of a small railway 

 station in a red plain. Out of the red plain rise 

 small rounded hills, all of them covered with the 

 same loose rounded boulders ; those on the east of 

 the rail at this spot being celebrated for the battle 

 which occurred on them on November 25th, 1899. 

 The country looks like a vast sea with islands 

 dotted about. The composition of these islands 

 became a matter of interest. They were all of the 

 same pattern, covered with a reddish soil, dotted 



as the column of troops wended along they crossed 

 the spurs of boulder-covered high ground, passing 

 along red soil down the talus slope; this thinned 

 down till the white limestone was exposed. The 

 lime would be succeeded by a modern " pan,'' i.e. ;i 

 water-bed, at this season (beginning of February) 

 generally dry, flat, sandy. In those districts where 

 there is an outlet from the hills a dam is built 

 across, and the dam end of the pan contains some 

 water ; and where there is water, there are one or 

 two trees and a farm. On the other side of the pan 

 comes the lime, then the red clay soil, then the hill 

 or kop. 



The foregoing is the structure of the country to 

 Bamdam, about nine miles from Enslin. The 

 travertine here is extensive and contains many 

 grains of garnet. A repetition of this sort of 

 country occurs as far as Waterval Drift. At 

 this spot came an interesting, but disappointing,, 

 series of strata. The Riet river flows past, the 

 " Drift " being the ford across that stream. The 

 river here has cut its way through thin strata of 





Fig. 1. Section of Plain near Exslix. 

 A. General surface level ; x Dolerite; — Stratified rock. 



with rounded boulders, the tops occasionally pre- 

 senting a cracked and fissured rock-bed from which 

 the boulders had come, while the slopes were so 

 covered with debris that the rock beneath was in- 

 accessible, except that now and then the debris 

 showed a shaly admixture. The red soil, formed 

 by the destruction of the dolerite, has washed down 

 across the plain, the boulders of the hills seldom 

 travelling far, and being always noticeably smaller 

 as the hills are descended. When the boulders in 

 the plain are larger than those at the foot of the 

 nearest hill, experience teaches that they indicate 

 the site of another doleritic prominence now dis- 

 guised by debris. (See fig. 1.) 



In the centre of the plain the ground is white, 

 and slight cuttings for the railway show that this 

 white soil — which, by the way, has given the homely 

 name of " Chalk Farm " to one of the stations a 

 little further south — is a travertine, varying in 

 thickness from an inch to five or six feet, lying on 

 denuded strata of shales. This white formation is 

 a striking feature of the country. Day after day 

 Jcly, 1900— No. 74, Yor.. VII. 



sandstones, and the disappointment consisted in 

 not being able to obtain a specimen owing to a 

 hurried move. While halting temporarily at a 

 deserted farm-house on the bank, the paving of 

 the verandah was seen to contain on some of the 

 stones, and on a flag-stone, the remains of plants. 

 However, had a specimen been obtained it could 

 not have been carried away, as a 50-lb. kit does 

 not allow of geological additions. As usual, the 

 strata in the river bed and bank were horizontal, or 

 nearly so, the usual characteristic of strata in this 

 country, even though outcrops or dykes of dolerite 

 occurred in the vicinity, as seen when morning 

 broke on a march commenced at 1 A.M. to the next 

 halt at Weydrei, near Jacobsdal. Circumstances 

 did not allow of any close examination of the 

 few exposures of stratified rocks at Klip Drift, the 

 next halt ; they were observed to consist of flags 

 with intervening sandy shales. Further up the 

 river, at Klip Kraal, sections of these flags and 

 shales were exposed ; but beyond noticing that the 

 shales were very dark-coloured, no close note was 



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