It appears that, in the Nile environment, all types may be represented' The heavy mineral analyses of all the samples have been formulated in Table 2. Seven types (C 1-2-3, F 4-8) are distinguished, according to the distribution of grain size, to which all the sediments in the fluviatile environments could be allocated. The coarser fluviatile sediments are especially well defined in this area by granulometric analyses. Only during floods and owing to the systems of irrigation practiced are sediments supplied to the soils. Under normal conditions transport of sediment in the channel is directed largely towards the sea. An outline is liven of the most important means of sediment transport and deposition in the Nile-Valley. The size-distribution analyses and the heavy mineral analyses of seventeen surface samples have been studied. The coincidence of ore shoots and alteration body with certain structural elements of the Casapalca anticlinorium is discussed. The results of a systematical thin-slide study of the rock type under discussion are in favour of alteration. Various opinions about the origin have been brought forward. In the centre of the mine in the single zone of the most conspicuous parallel vein system a body of rock has been intersected that does not fit in the stratigraphical sequence. The Casapalca mining district in central Peru is a source of lead, zinc, silver and copper ores of the lepthothermal type. The central alteration body of the Casapalca mines, Peru
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