252 Br. F. H. Hatch— 



resemble those of Hospital Hill, and, like the latter, are faulted 



up against granitic rocks." 



When at the close of the Boer War in 1902 I rekirned ta 

 Johannesburg, I had, as consulting engineer to Messrs. Lewis & 

 Marks, a good opportunity of renewing my researches in this district. 

 Messrs. Lewis & Marks held the controlling interest in Grootvlei 

 No. 45 and Palmietkuil No. 61, and, being anxious to prove the 

 value of these farms, were willing to spend a large sum of money 

 in boring. Lying mid- way betAveen the points where the Witwaters- 

 rand beds disappear under the Dolomite at Klipfontein and where 

 they re-emerge with dip reversed from below thot formation on 

 Marievale in the Heidelberg district, the ground could not, on my 

 theory, be far from the centre of the syncline formed by these beds, 

 and was, therefore, admirably situated for testing its validity. 



Having been given a free hand, I set to work by laying out an 

 east-and-west line of boreholes, which, together with one previously 

 put down on Geduld, extended over 10 miles of country. By means 

 of these borings I felt certain I should be able to locate below the 

 Dolomite the sub-outcrop of what I termed the " Van Ryn-Nigel " 

 reef. 



The first two boreholes were too far to the east, and, after passing^ 

 through 700 feet of Dolomite capped by Karroo beds, entered the 

 Lower Witwatersrand. The third borehole was abandoned by the 

 contractors while still in the Dolomite. The fourth entered a dyke 

 at the critical moment and was given up. All these holes were on 

 Palmietkuil . 



I then went to the western boundary of the farm Grootvlei, and 

 was successful there in striking the Van Ryn-Nigel, or Main, Reef 

 at a depth of 3,414 feet. The next borehole was on the boundary 

 between the two farms Grootvlei and Palmietkuil and struck the 

 reef at 2,376 feet. Two more holes were put down : one oa 

 Grootvlei, which struck the reef at 4,299 feet, and one jointly with 

 the Daggafontein Company, immediately south of the Grootvlei. 

 boundary, which intersected the reef at 5,540 feet. This last-named 

 hole was found by survey to have been deflected considerably from 

 the vertical — in fact, the horizontal distance between the mouth of 

 the borehole and the point where the reef was intersected in it was 

 2,225 feet. After making the correction necessitated by this 

 deflection, the vertical depth of the intersection of the reef was. 

 found to be 4,880 feet.i 



Five boreholes, therefore, gave sections of the Upper Witwaters- 

 rand beds, which in all of them are characterized by certain un- 

 mistakeablc features. These are : — 



^ The particiilars of this borehole were published in my report to the 

 Directors of the East Rand INTining Estates, Ltd., and issued in the Annual 

 Report to the shareholders for the year ending 30th June, 1905. The 

 particulars of the other boreholes and a general summing-up of the results 

 are given in my paper on " The extension of the Witwatersrand Beds eastward 

 under the Dolomite of the Southern Transvaal " : Trans, of the Oeol. Soc. of 

 S.A., vol. vii, 1904, p. 57. 



