Page:Quarterly Journal of the Geological Society of London, vol. 28.djvu/36

 period of their deposition ; but no recent fossils have been found in these gravels, although thousands of diggers have been working at them for many months. Only large quantities of worn fragments of fossil wood and two or three pieces of fossil reptilian bones, all from the older formations, have been met with.

The fragments of pierced Ostrich egg-shells found at Du Toit's Pan, although of considerable antiquity, evidently belong to a far more recent deposit, and have been buried in the silt of a " Pan " or " Fontein," which was the drinking-place of some primitive tribe of Bushmen.

The absence of recent remains and the frequent fragments of ancient fossils are of great value in the history of some of these gravels. Again, the worn and highly polished surfaces of nearly all the fossils and pebbles, together with the flattened and wedge-like shape of many of them, are highly suggestive. Running water would have rounded them. And not only are the small pebbles highly polished *, but very many of the large boulders have their surfaces smoothed and polished. In the excitement of diamond- hunting, however, few have thought of looking for striae or scratches upon any of them (see Postscript). Lastly, on the Diamondia side of the river, the rocks themselves marked 6 in the Section, fig. 2, have the same smoothed and rounded appearance.

The conclusions to be drawn from the foregoing facts appear to be these : —

1st. That large portions of the diamond-bearing gravels are not of local origin, but must have travelled long distances, gathering and carrying with them fragments of the various rocks over which they passed in every stage of their journey.

2nd. That, as many of their constituents are found in the Quathlamba or Draakensberg, it is highly probable that a large portion had its origin in that range, or in its northern offshoots.

3rd. That, although it has yet to be determined whether the fixed rocks that contain diamonds are to be found in the mountains mentioned, or whether these gems have been intermingled with the gravels at any intermediate stage of their passage downward to their present site, it seems certain, from the appearance of many of the diamonds discovered, that a large number must have travelled a considerable distance, and that the numerous broken ones have been fractured by the grinding power of the massive boulders with which they are so frequently associated.

4th. That the vast unstratified deposits, the promiscuous piling together and intermingling of boulders, the remarkable polish of many of them, the terrace-like mounds and accumulations, all evince physical conditions far different from those at present in operation ; while the entire absence of all recent fossils in these gravels almost forces upon us the conviction that they must have

elsewhere, as remarked by the Rev. W. B. Clarke, F.G.S., in his Address, Roy. Soc. N. S. Wales, May, 1870, who refers to drifting sand and silicated water as being probable agents under some circumstances. — T. R. J.
 * This peculiar polish of pebbles and fossils is observed in Australia and