214 Influence of the Physical Character 
property of carrying what water it does absorb directly 
downwards; when it reaches the next formation, which, in 
this country, is most often inclined clay slate, it will 
penetrate to great depths, and ultimately reach the sea, at 
much lower levels than the river basins, because, when the 
clay-slate rocks are secured from the action of the weather, 
they aredecidedly permeable. 
To show how water is retained on the surface of basaltic 
rocks, permit me to direct your attention to section No. 4, 
which is drawn across the basaltic hills near Melbourne. The 
hollow shown in the section is a swamp in winter, receiving 
the drainage water of the adjacent hills, where there are thin 
tertiary beds. ‘The trend of the land is toward the Saltwater 
River, but there is no true water course. The owner of the 
land has sunk a pit about four feet in depth, and he has 
obtained a small supply of water during this summer. It is 
by no means of good quality. This section shows the usual 
manner in which swamps occur on basaltic flats. 
In thus treating generally of the geological formations of 
this country I have omitted a description of merely excep- 
tional cases, such as crateriform hills, &c., &c. My object 
has been to shew that the thin tertiary beds are the principal 
reservoirs in this country. And according to the elevation 
of the land, and the prevalence of schistose rocks, so are 
these numerous and more extensive. 
Now instead of thirty feet of tertiary gravel and sand 
resting on paleozoic rocks, let us suppose a basin to exist in 
the district of Mount Alexander, somewhat similar to that 
shown in section No. 5. The granite in this instance is 
covered with a vast thickness of sandstones, shales, and beds 
of coal. The dip and arrangement of the strata are favour- 
able to the absorption and retention of water. The beds are 
disturbed by faults, which permit the water to descend with 
rapidity, as the fissures thus created are filled with sand or 
sandy clay. The rain, instead of falling on steep and naked 
ranges, whence it rapidly flows to the river basins, is received 
on well bosomed hills, and in gently sloping valleys. The 
alluvium of these valleys, like that resting on the clay slate 
rocks, becomes saturated, and the water, percolating through 
to the sandstone beds, is thence conveyed through innumer- 
able fissures and faults till it meets with an impermeable bed 
of clay. 
In strata, such as is shown in the section, it is not unusual 
to meet with two or more distinct sheets of water. At the 
edge of the granite, it will be seen several beds are basseting 
