T. S. Hunt on the Chemistry of Natural Waters. 179 
It is not certain that all the above reactions observed for 
chabazite are applicable without modification to the double hy- 
dro-aluminous silicates of sedimentary strata. Were such the 
case, important changes might, in certain conditions, be effected 
in the composition of saline waters. Thus, in presence of a great 
amount of a hydrous silicate of lime and alumina, solutions of 
chlorid of sodium might acquire a considerable amount of 
chlorid of calcium; but it is probable that these reactions, how- 
ever important they may be in relation to the soil, and to sur- 
face-waters with their feeble saline impregnation, have at present 
but little influence on the composition of the stronger saline 
waters, It is, however, not impossible that the action of the 
ancient sea-waters, holding a large amount of chlorid of calcium, , 
upon the hydrated and half-decomposed feldspars which consti- 
tuted the clays of the period, may have given rise to those double 
silicates which formed the lime-soda feldspars so abundant in the 
rador series. : 
phenomena intervenes, which are due to the deoxydizing power 
resent j . ee ‘ 
P 89. i: small quantities wit onal 
certain conditions, dissolved by waters holding organic acids. 
The existence of pi otite, a native compound of alumina with 
®0 organic acid, and the occasional association of gibbsite with 
2 Geology of Canada, p. 512. 
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