172 J. T. Jiitson: Salts in Rock Weathering. 



"Geological Magazine" for November, 1917, pp. 526-528, iu which is 

 raised the question of the chemical action of sodium chloride in addition 

 to the mechanical principle of crystallization. In this connection Dr. 

 Bather refers to the work of Professor R. C. Wallace, whose full 

 statement will be awaited with interest. 



EXPLANATION OF PLATE XXX. 



Fiffs. G. and II . — Sections illusti'ating undermining of rock cliffs 

 on shores of " dry " lakes. In G the small cavity may be regularly 

 continuous for some yards along the line of cliff. 



tig. I. — Undermining of granite on the western shore of a lake, 

 east of Lake Goongarrie, Comet Vale district. The rock floor is not 

 visible here. 



Fig. J. — Undermining and hollowing out of greenstone clifis at 

 the " Peninsula." Lake Goongarrie. A thin layer of silt covers 

 the rock floor here. 



