1871.] STOW VAAl-KIYER DIAMOJ^D-GEAVELS. 17 



been laid down under circumstances inimical to animal and ve- 

 getable life; and these circumstances, judging from similar de- 

 posits in other countries, have been brought about by the action 

 of ice. 



5th. That such gravels as those marked E, F, and G, in Section, 

 fig. 2, were probably rearranged from more ancient gravels in a trough 

 eroded in the rocks forming the floor of the Yaal valley. 



In compiling this paper I have been greatly indebted for notes and 

 descriptions to Messrs. Shepstone, Donald, White, Kedger Tucker, 

 Cronin, Key, Scott, Ella, Southey, Graham, Whitmore, and several 

 other gentlemen. 



Postscript, July 6, 1871. — Since writing the above, I have been 

 informed by Mr. Tobin, who has travelled aloug the valley of the 

 Yaal from the Draakensberg to Pniel, that he has traced agates 

 along its entire course, and that at Harrismith, twenty-three miles 

 on the Eree-State side of the mountains, a very extensive zone of 

 fossil wood makes its appearance. Mr. Tobin also showed me some 

 sketches of the road over the Draakensberg, which reminded me 

 forcibly of the peculiar rounded (glaciated) contours that I described 

 in my former paper as noticeable in the Katberg*. 



Lastly, Mr. George GilfiUan, who is at present on a visit to 

 Queenstown, tells me that a short time ago he discovered near 

 Pniel a large boulder with strice distinctly marked upon it, and 

 that since then he found at " Moonlight Ensh " that almost every 

 boulder in the gravels there has most unmistakable markings of the 

 same kind upon one or more sides. This appears to me a most sa- 

 tisfactory and important discovery with regard to the deposits we 

 have been considering, and one which must definitely settle the ques- 

 tion as to the conditions under which many of them were laid down. 



G. W. S. 



AppejSdix. — Desceiptiox of Specimens sent hy Mr. Siow. 

 By Prof. T. Etjpert Jones, E.G.S. 



In a letter, dated October 10, 1871, Mr. G. W. Stow states that, 

 after a three week's visit to the Yaal-PJver Diamond-fields, he feels 

 certain the description given of the diamond-gravels in the foregoing 

 paper is correct, and that no other agency than that advocated in it 

 could have formed the accumulation of boulder- drift, the river- 

 deposits being distinct. 



In determining the nature of these specimens, Thomas Davies, 

 Esq., E.G.S., of the British Museum, has kindly given mo his 

 assistance. 



No. 1. From Gong-gong. See page 7. 



"Washed, coarse, agate gravelf, containing : — ' 

 Yeined Jasper, one pebble. 

 Yellow and white Quartz, several peblles. 



* See Quart. Journ. Geol. Soc. vol. xxvii. p. 539. 



t A small dressed (?) fragment of rock-crystal was sent with this parcel. 

 VOL. XXVIII. PAUT I. C 



