Mineral Waters of Victoria. 279 
all the water that falls on the surface of the earth passes 
into the soil and from thence through joints and fissures, or 
_ by percolation through porous rocks, downwards and becomes 
‘subterranean. This water is always more or less charged 
with carbonic acid, and in passing through rocks which are 
composed of silicates, it decomposes them, forming carbonates 
of the alkalies, and alkaline earths. If the carbonic acid is 
in excess, the whole of these will be carried away as bi-car- 
bonates or simply held in solution by it, for Fresenius has 
shown that the carbonates of lime and magnesia are soluble 
in water containing much less carbonic acid than would be 
required to convert them into bicarbonates. But if there is 
not sufficient carbonic acid to carry off these substances they 
would remain in the rock as carbonates, thus increasing its 
volume and, as Bischof states, in some cases it must give 
rise to a mechanical force of expansion capable of uplifting 
the incumbent crust of the earth, or acting laterally, com- 
press, dislocate, and tilt the strata on each side of the mass 
in which the new chemical changes are developed. 
Instances of the first kind spoken of; in which carbonated 
waters have decomposed granite and carried away everything 
except quartz and silicate of alumina (kaolin), may be seen 
in many places in Victoria, as at Bulla Bulla, Dunolly, and 
Kyneton. The street-cutting at Flagstaff-hill shows a good 
section of more or less pure silicate of alumina ; the original 
rock undoubtedly belonged to the older basaltic formation, 
and was at some period, for the most part, hard, dense 
basalt. 
- An instance of the second kind may be seen in the green- 
stone of Mount Camel, a few miles north of Heathcote, 
which contains carbonate of lime as calcite: this mineral has 
probably been derived from the rock itself, a specimen 
of the rock procured by Mr. Norman Taylor, of the Geologi- 
cal Survey, contains calcite in veins and firmly imbedded be- 
tween the crystals of pyroxine and feldspar, of which the 
rock is composed., Mr. Taylor states that the rock in place 
has all the appearance of a stratified rock, but upon examin- 
- ing the specimens, I find these lines which resemble strati- 
fication to be lines of decomposition, leading to masses of 
calcite. 
The country near Mount Camel has not been subjected to 
a detailed geological survey, which would be required to de- 
tect the result of the expansive force which must have fol- 
lowed the chemical change in the rock. 
