October, 1929 
The Queensland Naturalist 
45 
Geologists have for many years shown a desultory 
interest in the relationship of soils to their parent rocks. 
Consequently the Pedologist has inherited a small store 
•of facts of observation and some rather crude ideas with 
.regard to soil processes. 
The new science of Pedology was established early in 
•.this century by a group of Russian scientists, chief of 
whom was Glinka. The huge extent of the Russian 
provinces, embracing as they do a varied assortment of 
geological, geographical, and climatic conditions which 
were yet found in one continuous land mass, formed an 
.excellent field for the study of the origin and formation 
tof soils. 
The methods of the Russian pedologists have now 
been adopted by the United States of America. It is 
because their methods are eminently suitable for our own 
wide land of Australia that I have had the temerity to 
introduce the subject to you this evening, for I am not 
.a pedologist — I am a geologist. 
Soils can be roughly divided into two great groups. 
The first group includes all those which have been carried 
to the position which they now occupy through the agency 
■of wind, ice, or running water, and which therefore bear 
no relationship to the underlying rock floor. These are 
.known as soils of transportation. They include great 
.areas of valuable alluvial soil, and are often of great 
importance from the economic point of view, but they are 
(•of little help to the pedologist. The other great group 
is made up of soils formed in situ, and which are there- 
fore directly related to the underlying rocks, although 
they may be very dissimilar from them. These may be 
‘Called the sedentary soils, and it is with this group that 
1 wish to deal particularly. 
The nature of these sedentary or residual soils must 
in the early stages of their formation be largely controlled 
by the nature of the underlying parent rock, but it is the 
principal thesis of modern pedologists that it is climate 
which is ultimately the dominating factor, and that in 
the end when the soil has reached equilibrium with its 
■environment it may not resemble even remotely the rock 
from which it has been formed. 
Those sedentary soils which have not yet attained 
equilibrium with the local climatic conditions, but still 
show to a greater or less extent the influence of the 
parent rock, are known as “Immature Soils, M while those 
which have reached stability under the existing climatic 
^conditions are called “Mature Soils. 7 7 
