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Ni^NCY T, BuRBIDGPi. 
Across Nalgi and the southern section of Anna Plains is a curious tall 
shrub zone. The zone varies from under a mile to several miles in depth. 
The zone has two features worthy of comment. Firstly, just south of the 
Nalgi boundary is an area with numerous “blowholes'^ from a few inches to 
several feet in diameter. The depth of these is unknown. From surface 
indications the limestone here appeal’s to be different in nature from that 
of the coastal sandhills. Secondly, through the blowhole country there are 
a. few short drainage channels. Apart from these the whole area dealt with 
in this paper is entirely lacking in defined water courses. 
Small ])atches of this shndiland occur in some jdaces on Wallal but 
there is not a continuous zone as there is further north. There is no other 
outcrop of blowhole limestone. 
Other features of interest on the coastal jdain are occasional red sand 
ridges. The soil appears to be intermediate in character between the pindan 
sand and the coastal type. The former has possibly been left there as a 
result of wind action. Ea.st or south-east winds are of almost daily occurrence 
over many months of the year. Such ridges are usually near the junction of 
the pindan and the plain. In some cases the ridges have outcrops of the 
coastal sandy limestone. 
p]COLOGY. 
As has already been said the area may be divided into two main zones, 
i.e., the coastal plain and the spinifex pindan. However, the whole region 
belongs in the great ecological region Avhich .stretches from the Ashburton 
River to the Fitzroy River. This area is nearly all spinifex country, i.e., 
species of Triodia R.Br. dominate the landscape. Along the SO-Mile Beach 
there are just the two phases of the ecological type to discuss. Triodia 
jningens R.Br. is the dominant species and often th(‘ only grass present. 
Various other arasses are important in different sections but thev will be 
