The thesis describes in detail the area of the uranium lodes in
the South Alligator River valley in the Northern Territory of
Australia. The four land forms are described, together with the
soils developed on them, and the morphological and genetic
relationships of the latter are discussed. The published
stratigraphy of the area is recapitulated, and some changes of
viewpoint are advocated: an unconformity within the Upper
Proterozoic rocks is described; the characteristics of the
Scinto Breccia unit are ascribed to silicification of diverse
stratigraphic units; the allegedly organic origin of calcareous
rocks of the Koolpin Formation is disputed; and the lack of
obvious signs of unconformity between the Stag Creek Volcanics
(Archaeozoic?) and the Lower Proterozoic sequence is pointed
out. A petrological study of a collection of rocks from the area
is made, and this includes a description of some diaspore-rich
volcanics in which the uranium mineralisation appears to be of
syngenetic origin. The characteristic