Page:Quarterly Journal of the Geological Society of London, vol. 28.djvu/30

 Those at the former locality are smooth and polished, and, where exposed to the action of tlie weather, black on the outer surface ; but where covered, of a reddish hue. They are close, hard, and compact, with a felspathic (?) character. At another spot, a section of them is given as follows (fig. 3) : —

Fig. 3. — Section of Supposed Metamorphic Rocks on the Vaal River.

1. Whitish quartz.

2. Quartzose rock.

3. Rock similar to b in the large section (fig. 2).

It appears highly probable that at one time these rocks from b to b (see the Section, fig. 2) have been eroded into a wide trough, in which the more recent gravels, e, f, and g, have been laid down. These gravels are evidently of a more recent origin than those at the higher levels, and are most probably composed of materials from the older gravels. The gravel and boulders are intermingled in the most confused manner ; and the several bands have irregular lines of bedding, and are rather contorted, appearing different from what might have been expected if laid down simply by fluvial action. This deposit was at one time very extensive in this locality, stretching across the present course of the river, and for a considerable distance along the bank of the Hebron side (see Map, Pl. I.). The stream, before it cut the new channel through these gravels, must have occupied an ancient river-bed, which, like the one at Cawood's Hope (p. 6), is now left dry, and traversed by flowing water only at the time of a very high flood.

Du Toits Pan. — With regard to Du Toit's Pan, which is rapidly becoming the chief centre of attraction to the diggers, I have not been able to obtain a trustworthy section, nor sufficient data to form a decided opinion upon the diamantiferous deposits in that

sive sections 1 have lately made, it crops up through them ; or, rather, the denudation has been so great in several places that it is exposed. This seems to be corroborated by information given to me a few days ago by Mr. H. Southey, who says that in the district of Middleberg, near the Rhenosterberg, there is a strip of country, stretching from the Orange River, with "pans " of exactly the same character as those between the Modder and Vaal, and that at two of them (Groote Fontein and Klip Riff, between Middleberg and Craddock) numerous garnets have been picked up which seemed to him to be similar to those from Du Toit's Pan.— G. W. S., July 6, 1871.