Geochemical data on Australian granites and pegmatites9 and the.,mineral.components of these rocks, is presented and compared with that obtained in similar studies in.the U.S.S.R and:.elsewhere._x000D_
The petrochemical character of tin granites and the trace.-chemistry of their component minerals, particularly biotites, have some significance as ore guides in prospecting for tin._x000D_
The primary geochemical dispersion of tin can be readily tested both in the laboratory and field by colourimetric methods, after volatilization with ammonium iodide, using modifications of.the method described by Wood (1958)._x000D_
Secondary dispersions of tin in residual soils or.alluvia can likewise be readily tested by rapid colourimetric methods in the field, but simple hydraulic methods,.handling larger-._x000D_
sample volumes, give reliable outlines of dispersion patterns.