242 
W. F. Cole. 
It is hence suggested that in the weathering of glauconitic greensand the- 
glauconite alters firstly to a clay of the montmorillonite group which later is 
replaced by a clay of the kaolinite group together with free quartz and haema- 
tite and /or goethite. The formation of kaolinite through the splitting off of 
silica from montmorillonite has been suggested by Kelley et al. (13) as an 
explanation of the occurrence of kaolinite clay overlying montmorillonite clay 
in the Suscjuehanna soil colloids. 
It is quite logical to expect on this hypothesis that kaolinite would be 
present with montmorillonite in the subsoil fraction but it must also be borne 
in mind that contamination of the subsoil fraction with the overlying soil 
would give kaolinite in the subsoil fraction. Such a contamination of the 
subsoil fraction is considered to be negligible. 
Table IV. 
COMPOSITION OF THE THREE SAMPLES. 
(From X-ray evidence only). 
Mineral. 
C})per Greensand. 
Subsoil. 
Soil, 
Coarse. 
Fine. 
Coarse. 
Fine. 
Coarse. 
Fine. 
Glauconite 
much 
Much 
Little 
Little 
Possible 
trace 
Possible 
trace 
Quartz 
Little 
Very 
little 
Much 
Very 
little 
■\'ery 
much 
Little 
Montmorillonite . . . 
Possible 
trace 
Possible 
trace 
Much 
Much 
... 
... 
Kaolinite 
... 
... 
Little — 9 
^ Little 
Possible 
trace 
Much 
Haematite and/or 
Goethite 
Tery 
little 
... 
Possible 
trace 
Little 
Little 
Xote . — An arrow ( — >•) indicates an inereawing amount of kaolinite. 
ACKNOWLEDGMENTS. 
The investigation was carried out in the Physics Department of the 
Univwsity of Western Australia during tluj tenure of a Haekett Research 
Stu(l('ntship and a Commonwealth researcli grant. The author wishes to 
express his thanks to tlie University of Wevstoru Australia for the former and 
to the Council for Scicnt ilic and Industrial Research for the latter. The X-ray 
equijnnent was originally providetl by a Commonwealth gi-ant. Tlie author 
greatly appn'ciatc^s llie facilities that have been made available through the 
Council foi- Scientilic and Industrial Research for carrying out the work. 
The |.u’ohi('m was suggested by Professor E. de C, Clarke and Dr. D. Carroll 
of the De])artment of (Geology of the University of Western Axistralia to whom 
the author is inde))ted for the pro\ ision of samples and apparatus and for many 
helpful discussions. 
The work was carried out under the supervision of Mr. J. Sliearer of the 
De])artment of Physics of tlie Lmiversity of Western Australia to whom the 
authoi''s tlianks are due for the checking of the X-ray data and conclusions and 
for \'aluable advice and criticism w’hi«‘h has alw'ays been freely given. 
