''Clawing" Action of Rain, 21 



:those covered by a sandy loam, the rain passes over the film in thin 

 sheets or rills without furrowing the ground, despite the latter 

 having many spaces bare of vegetation. Where the film becomes 

 broken by any means, miniature waterfalls occur, due to the flow 

 .of water over the film to the softer soil beneath. Tiny cliffs are 

 thus formed. 



These tiny cliffs may be only from an inch to six inches in 

 height, but they may extend laterally — that is, approximately at 

 right angles to the direction of water-flow — for many yards, and 

 thus form a miniature soil terrace on the slope. Other similar 

 terraces may form above and below; and thus on a gentle slope 

 several such terraces may be seen rising one above another, sepa- 

 rated by varying distances, but usually fairly close together. 



The actual outline of a terrace (see Plate II., Fig. 1) may be de- 

 scribed a-s a series of gentle curves or scallops, mostly concave to the 

 ground at the foot of the " cliffs," and each curve usually presents 

 a minutely crenulated edge. This appearance suggests some force 

 that has gently clawed away the soil, and hence the writer terms 

 the rain action ''clawing," Tiny furrows may run from the 

 "clawed" edges, indicating the directions of the minute rills. 

 These furrows usually tend to unite within a few feet from . the 

 edges into a larger one, but within a few more feet this larger 

 furrow dies out, owing to the action of the water in depositing 

 .the transported fine sand and soil as a series of minute, flat alluvial 

 fans or " lobes." The surface of the lower ground by reason of 

 such deposit becomes levelled off, thus illustrating, on a very small 

 scale, one result of rain action in this country. Another general 

 result is the slow transportation by rain of soil from higher to 

 lower ground. 



Extensive areas of rock fragments slowly drifting from higher 

 to lower ground form one of the commonest surface features in 

 sub-arid south-central Western Australia; but only the most resis- 

 tant rocks, such as quartz, jasper and ironstone, travel any dis- 

 tance. On the soil-covered terraces, such loose pieces of rock often 

 occur; and, as "clawing" proceeds, these fragments are seen in 

 x:ourse of being undermined. Eventually they topple over to the 

 lower level, and by repetition of this process their migration down 

 the slope is largely accomplished. 



