SCIENCE- GOSSIP. 



of the spur, and to feel on the western side. These 

 rocks are more or Less visible all round the spur, 

 while the top consists of dolerite. These sandstones 

 consisl of gijits above, firm sandstone in the centre, 

 and below fine white sandstone, with occasional 

 intervening layers of shale The grit at the top 

 has the appearance of having been denuded, then 

 irregularly covered by a narrow band of shale, 

 while overlying the shale, and following an uneven 

 surface, comes the dolerite sheet which evidently 



overflowed Er the extrusion at New Fort Kop. 



The denudation is again shown on a continuation 

 of this spur, where there is another small quarry. 

 Here the top shale and sandstone have been fur- 

 rowed out to the depth of about 15 inches, the 



the centre of a basin, the circumference of w] 

 is composed of dolerite. Altogether about 25 feet 

 of sandstone are more or less exposed hen-, there 

 being a slight outcrop of yellowish sand-tone above 

 the quarry, and the same of a buff sandstone below, 

 while the straight-cut wall of the quarry, which 

 niiw forms a reservoir for water, shows some 20 feet 

 of grey freestone. At. two levels in this freestone 

 are large and sonict imes curiously shaped bouldi rs, 

 which on section show concentric rings formed 

 round a central rolled stone, sometimes sandstone, 

 sometimes quartzite. The level of the top of this 

 quarry is no feet below that of the bottom of the spur. 

 To the east of Rustfontein Quarry Hill is a valley, 

 the opposite side of which is formed by a hilly 



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channel thus formed being filled in by dolerite. 

 which also covered the adjacent surface. The 

 height of the spur is about 80 feet above the top of 

 New Fort Kop, which again is 165 feet higher than 

 the buff sandstone before referred to, as that from 

 which the measurement of the stratified rocks is 

 taken. The top of New Fort Kop is the same level 

 as the lowest sandstone on the spur ; sothatitmay 

 be assumed that there are 210 feet of stratified 

 rock to be accounted for, the upper 35 feet of 

 the above 80 being dolerite. Of these the top 

 45 feet are seen on the spur, and the lower 80 feet 

 on the south and east of New Fort Kop, leaving a 

 gap of 85 feet. On the west of the spur, as well 

 as on the east, is a gentle slope of diluvial soil, 

 which conceals the missing strata, but they are 

 represented in other localities. The eastern side 

 of the spur has also been quarried, showing at a 

 lower level than the one in fig. 3 sandstones with 



boulders. 



About \h mile north of these quarries on the 

 spur is another and more extensive quarry at 

 Rustfontein in layers of sandstone which now form 



ridge running about N. and S.. and presenting 

 four conical points ; the most southerly and the 

 third from the south show on the eastern and 

 southern faces sandstones, the second and fourth 

 and the western side of the others are dolerite. 

 while the undulating country to the north is entirely 

 dolerite. These sandstones on the southern end 

 of the ridge are almost horizontal, and are inter- 

 stratified with thin layers occasionally of shale ; 

 the highest stratum is a fine grit, and is below the 

 level of the Rustfontein Quarry : the series extends 

 downwards (>7 feet. The sandstones on the third 

 hill from the south are crushed and distorted in 

 several directions which are difficult to unravel, 

 owing to the very partial exposure of the rocks. 



About a mile north-west of the spur is a kop 

 which maybe named No. 2 Picquet; its dolerite 

 cap covers sandstones, the topmost being soft and 

 white ; at its base is a sandstone, underlain by a 

 thin layer of quartz gravel, and this again by shale. 

 The level of this quartz gravel is 25 feet below that 

 of the base i>t' tin 1 spur, and 50 feet below the top 

 sandstone on No. 2 Picquet Hill. From this point 



