Reviews — Dry Lakes and Lands of W. Australia. 521 



at the Gatty Marine Laboratory at St. Andrews, it was shown that 

 the action was one of suction accompanied by scraping. 



W. H. W. 



VIII. — The De,y Lakes anb Lands of Western Australia. 

 Erosion and resulting Land Forms in sub-arid Western Australia,. 



INCLUDING the OrIGIN AND GrROWTH OF THE DkT LaKES. By 



J. T. JuTSON. Geogr. Journ., pp. 418-37, 2 pis., December, 1917. 



On THE EORMATION OF "NATURAL QuARRIES " IN SUB-ARID WeSTERN 



Australia. Ey J. T. Jutson. Proc. Hoy. Soc. Victoria (n.s.), xxx, 

 pp. 159-64, pis. xxviii, xxix, March, 1918. 

 The Influence of Salts in Hock Weathering in sub-arid Western 

 Australia. Tom. cit., pp. 165-72, pi. xxx, March, 1918. 



rilHE dry lakes of the Salt Lake Division, north of Coolgardie and 

 JL Kalgoorlie, have been ascribed by some authors, e.g. C. G. Gibson 

 and J. W. (Jregory, to river-systems of Tertiary, probably Miocene, 

 time. H. P. Woodward believed them to be Avind-planed flats. 

 Mr. Jutson, while admitting the possibility of Miocene rivers, does 

 not believe that there can be any direct connection between them 

 and the present lake system. Given an undulating surface, such as 

 the present contour of the country suggests, then, in his opinion, the 

 existing agents seem competent to produce all the existing 

 phenomena, including valleys, plains, and lakes. The lakes appear 

 to have been formed by the processes of advancing sands, formation 

 of sand-bars, recession of lake-shore cliffs, and planing and hollowing 

 out of rock floors. These processes have resulted in the formation, 

 dismemberment, migration, growth, capture, and union of lakes. 

 Many factors are responsible for the results obtained, amongst 

 which the wind is regarded as playing a prominent part. 



The "Natural Quarries" are circular, rectangular, and triangular 

 excavations, resembling artificial quarries, in the hillsides of various 

 rocks. Mr. Jutson believes that they are due to the undermining 

 action of rain under special conditions, which he describes. 



While the action of wind and the variations of temperature are 

 important agents in producing the configuration of the sub-arid 

 region, as they are in other deserts, something must also be assigned 

 to the crystallization of salts contained in the rocks in solution and 

 brought to the surface by capillary attraction, when the water then 

 evaporates. By the expansion due to crystallization flakes or grains 

 may be forced off or a soft rock may crumble. To such a process 

 Mr. Jutson restricts the term " exsudation ". It is chiefly observed 

 at the base of cliffs at the edge of a dry lake. It undermines 

 tlie cliffs and the debris are carried away by wind, so that the 

 billiard-table floor is produced. It is curious that no pronounced 

 efflorescences have been noticed in these situations, though they 

 seem to occur on rocks that are more exposed to the sun. 



F. A. B. 



