89 
has been longer exposed to the washing action of the rains, and 
has been more thoroughly leached of salt than the parts which 
were later in emerging. The snb-aerial theory might explain the 
accumulation of the salt in the lowest parts of the plains where the 
water gathers, l>iU it does not explain why the South Coast region 
which has twice or thrice as great a rainlall as the country further 
north should be the saltest portion of the State. 
The salt waters found in our salt areas vary greatly in total 
jiercentage of saline constituents per unit of water, and also a 
good deal in the relative amount of the various salts jiresent, but 
it is very notable that the salts iiresent are principally those also 
found in sea water, and are such as might result from the leaching 
of sea salt from superficial sediments. In this process certain 
reactions are liable to take place between the salts and the constitu- 
ents of the soil which may have the effect of rendering some jxir- 
tions of the former insolubie, with interchange of other soluble salts 
not originally in the sea water in ])lace of them. The calcium 
sulphate in sea water, for example, might readily react with sodium 
carbonate formed by the weathering of sodium-bearing silicates in 
the soil, to form the much less soluble carbonate ot lime and 
sodium sulphate. Many such reactions must be exjiected which 
might soon alter the quantitative proportion between the various 
salts from that normal in sea water. Taken on the whole, the salts 
in our salt lakes and wells may truly be said to be of a marine 
facies, sodium chloride being always predominant, and constantly 
associated with much of suliihates of lime and chlorides and sul- 
phates of magnesia, in some cases the magnesia salts are more 
plentiful than usual, and the composition of the saline constituents 
of the water then a])proaches that of the ‘*l)itterus” formed when 
])art of the sodium chloride of sea water has been crystallised out 
of it. Whether such removal of sodium chloride he the reason of 
the relative excess of magnesium salts or not, it may be noted that 
very similar variations in the proportions of sodium and magnes- 
ium salts arc couimou in brines pumped from saline strata in salt 
producing districts. In these, too. a like differential removal of 
certain of the salts must have taken place as the marine origin of 
these salt beds is undis])iUe<k and the proportions of the 
salts present must therefore have been originally those normal in 
sea water. 
d'he insufficiency of the theory that the salt in the ocean is 
derived from mere evaporative concentration of the salts brought 
down by rivers has frequently been remarked upon. Julius Roth, 
for example, found that the proportions of the salts of river and 
sea water were : — 
Carbonates. Sulphates. Chlorides. 
% % % 
River water .... 80 13 7 
Sea water 0.2 10 89 
