Krasnozems of Innisfail — Monteith 
377 
heavy mineral ratio is often a guide to the 
origin of the soil material. A low ratio reflects 
a basic rock origin, and a high ratio an acidic 
rock origin (Carroll, 1949:23). However, it 
could indicate a certain weathering stage (Jack- 
son and Sherman, 1953:239), since a low ratio 
may represent a highly weathered soil of either 
basic or acidic rock origin. 
Zircon and T ourmaline 
The presence of zircon and tourmaline shows 
that some of the soil material is of acid and 
intermediate igneous rock origin (Milner, 1940: 
355). These minerals can survive several erosion 
cycles and are accompanied in these soils by 
minerals (magnetite, quartz) which can also 
survive several cycles. It is most likely, there- 
fore, that the Daradgee and Mundoo soils are 
derived from reworked sediments. The Euben- 
angee soils show some evidence of this, but the 
Pin Gin soils do not. 
X-Ray and D.T.A. Data 
These data show differences in kaolin and 
gibbsite content from the gibbsite-dominant 
Mundoo soil to the kaolin-dominant Daradgee 
soil. According to Jackson and Sherman (1953: 
239), the classification of these soils into their 
order of weathering based on kaolin, gibbsite, 
and goethite content would be: Mundoo soils 
(most weathered), Eubenangee soils, Pin Gin 
soils, Daradgee soils (least weathered). 
"Free” Iron 
The free iron content shows the Eubenangee 
soil to be highly weathered and, because of the 
relatively low figures for a well weathered soil, 
appears to confirm the impression that the Mun- 
doo soil is not of basic rock origin. 
Field Observation and Mineralogy Studies 
The field observations (given under soil 
descriptions) are largely confirmed by the 
mineralogy studies. 
The Pin Gin soil is derived primarily from 
the basaltic material in the lower profile, and, 
while it is of recent origin, has weathered 
rapidly to produce some gibbsite and goethite. 
The parent material of the Eubenangee soil is 
largely basalt. However, the presence of zircon 
and tourmaline shows that some material is of 
acid rock origin. Therefore, it is colluvial ma- 
terial from mixed sources which (according to 
the gibbsite, goethite and free iron content) has 
been highly weathered or has derived from 
highly weathered sources. The Daradgee soil 
shows ample evidence that the material has 
been reworked and is partly of nonbasaltic 
origin. The weathering stage is not advanced. 
Similarly, the Mundoo soil consists of reworked 
sediments (shown by the high tourmaline and 
zircon contents), but, inasmuch as it contains 
a large proportion of gibbsite, it is highly 
weathered. From the presence of this soil 
beneath post-Tertiary flows and the occurrence 
of a general laterisation period in the Pliocene 
(Connah and Hubble, I960), it is assumed 
that most of the weathering process took place 
in the Pliocene. The soil remained buried by 
basalt flows until recent times. 
It is of interest, then, that these four soil 
series, classed generally as krasnozems or lateritic 
krasnozems, have different origins and have 
undergone different weathering processes. 
Fertility Status and Weathering 
Much has been written about the correlation 
of soil classes with fertility status and crop or 
pasture production (Butler, 1964). The general 
conclusion appears to be that there is little cor- 
relation between series and that the variation 
from series to series is as high as that within 
the series. This is especially so in sugar cane 
growing regions which have been growing cane 
for up to 50 years (Monteith, 1949). In this 
case, however, the soil type can be related to 
production in the initial establishment period. 
The Mundoo soil was abandoned for cane grow- 
ing at one stage and has been brought back into 
production only by the use of factory filter 
waste, molasses, and great amounts of fertilizer. 
The soil has been the most infertile of the four 
in the Pin Gin family. The establishment of 
cane growing was difficult on the Eubenangee 
soils also, but growth responded well to factory 
filter waste and superphosphate. The Pin Gin 
and Daradgee soils have not proved to be diffi- 
cult soils for cane growing. The order of fertil- 
ity in the early period of cane growing is, in 
this case, similar to the order of weathering. 
Therefore, a mineralogical appraisal of virgin 
