137 



after olivine. Magnetite is present in moderate quantity, 

 and also leucoxene. Traces of limonite and haematite are 

 also present. This rock is not similar to any specimens of 

 the Mount Gambler basalt which we have at hand for com- 

 parison, but in general character it is like some of the Mel- 

 bourne basalts. The question that arises is from what locality 

 and by what means did it become transported to its present 

 situation ? 



Division 3. 



JANJUKIAN (mIOCENE) MARINE BEDS. 



Section A. 



GREEN AND YELLOW CLAYS AND SANDS. 



These are soft clayey and sandy beds, often notably 

 calcareous, of greenish or buff colour. Yellowish and reddish 

 mottlings and streaks may appear where these beds rise 

 above ground water level, thus exposing the iron content to 

 oxidising influences. 



In some portions of the field borings have revealed strata 

 in this section of the beds of great uniformity. In such cases 

 a general buff colour is assumed. The greenish tint due to 

 glauconite granules, which is an outstanding feature in other 

 areas, is, in these situations, largelj^ suppressed. In all cases, 

 however, at least a little glauconite can be detected, on close 

 examination. Tlie buff-coloured silt forming the bulk of such 

 beds is exceedingly fine-grained and of low specific gravity. 

 The average grain size amongst the observable discrete par- 

 ticles in one of the finer bands proved to be 1/100 of a 

 millimetre diameter. The coarser particles are well rounded 

 except for very minute flecks of mica. The sand grains of 

 the coarser beds of this series are unusually rounded and 

 polished. In fact, a large part of these buff -coloured sedi- 

 ments is loessial in character. Such beds are particularly 

 well represented in a bore at the cross roads, some two miles 

 north of Moorlands station. Tlie buff-coloured component 

 of this sediment possibly originated as wind-blown dust from 

 the interior of the continent, picked up and transported by 

 the ancestral Murray-Darling River system. Judging from 

 the highly glauconitic character of some of the beds, such were 

 probably laid down in current-disturbed waters at a con- 

 siderable depth. 



Fossils are reasonably common only in the more highly 

 glauconitic portions of this section. One such bed of a bright 

 apple-green colour and of a calcareous nature was examined 

 in detail for fossils. Polyzoa were found to be comparatively 

 numerous and rotaline foraminifera not uncommon. Besides 



