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| Keywords: The Quarterly journal of the Geological Society of London (13889884388).jpg LTDENBUEG AXD DE KAAP TRANSVAAL SOUTH APRICA <br> 583 <br> The gold lodes consist of main qnartz-reefs and transverse leaders ; <br> These leaders are thin a few inches onlj- in thickness and <br> consist partly of white quartz partly of oxide of iron and man- <br> ganese Two of them sometimes merge into one and occasionally <br> two or more unite to form a main lode close to or in contact with <br> the dyke Almost without exception the gold-mines of this district <br> are in such leaders in proximity to diorite dykes An average <br> yield of 4 oz of gold to 2000 lb of quartz was the estimated <br> result of several examinations <br> Several main and branch dykes of diorite are traceable for long <br> distances and in some instances are well exposed in the open mines <br> In two cases the shales are sharply tilted by the dykes on the west <br> w <br> Fig 3 ” Section of Diorite Dyhe Lishon-Berlyn <br> E <br> a Tilted shale <br> b Dyke <br> side and in one on the east they are slightly contorted on the other <br> side In the section the weathering leaves hard kernels of blue <br> diorite with concentric rings semidecomposed shading off into the <br> soft brown mass which otherwise resembles an alluvial loam <br> v A few miles S W of Waterfall are the farms about Pilgrim's <br> Rest belonging to the Transvaal Gold-Land-and-Exploration <br> Company The rocks here are higher in the series and are more <br> siliceous in character the lower main mass of chalcedolites being <br> in considerable force Their chief outcrop however is along <br> the west side of the Blyde Eiver Here also are many diorite <br> dykes one of which a small branch dj'ke in Pilgrim's-Eest Creek <br> has tilted the adjacent beds inversely to the usual position <br> With the exception of the rich alluvial deposits in the creek the <br> ground chiefly worked here for gold has been the rotten-reef <br> similar to those previously described The chief of these are at <br> Erown's Hill and Ophir Hill ; but I have no data upon which to <br> base an opinion as to their value which is regarded as high <br> Crossing the Blyde and mounting the steep escarpment to the <br> west we find shales cropping out from top to bottom with the ex- <br> ception of the upper of the two main series of chalcedolites inter- <br> vening part way up the hill The shales have generally a small <br> westerly dip but are locally thrown to high angles and into various <br> positions by plutonic dykes The chalcedolites are much decom- <br> posed and a bed of quartz at least one foot in thickness is seen <br> amongst them On the summit of the hill is a series of crystalline <br> sandstones 37047463 114009 51125 Page 583 Text 41 http //www biodiversitylibrary org/page/37047463 1885 Geological Society of London Biodiversity Heritage Library The Quarterly journal of the Geological Society of London v 41 1885 Geology Periodicals Smithsonian Libraries bhl page 37047463 dc identifier http //biodiversitylibrary org/page/37047463 smithsonian libraries Information field Flickr posted date ISOdate 2014-04-30 Check categories 2015 August 26 CC-BY-2 0 BioDivLibrary https //flickr com/photos/61021753 N02/13889884388 2015-08-26 04 58 59 cc-by-2 0 PD-old-70-1923 The Quarterly journal of the Geological Society of London 1885 Photos uploaded from Flickr by Fæ using a script | ||||
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