THE GEELONG NATURALIST. URL 
cated a valuable series of observations on the sand dunes of 
Victoria. 
Now we have come to the examination of the rock 
hy made up of the consolidated dune material, we notice a 
marked irregularity in its bedding—no bed is uniform in 
thickness for any great distance, but rapidly thins out, 
frequently in both directions from the thickest part, giving rise 
to the frequent recurrence of lenticular patches, one succeeding 
another. In bedssuchas thesethe dip is constantly changing 
in direction and amount, and these peculiarities give rise to 
what is termed ** False Bedding.” If welook back and see how 
the dunes are built up it is not long before it becomes evident 
that this false-bedded structure is formed owing to the way 
in which the wind accumulates the sand, layer upon layer, 
firstin one direction, then in another. False bedding, or 
current bedding, as it is sometimes called, is not found in 
zolian rocks alone, but is not uncommon in sandy beds or 
sandstones oflacustrine, or marine origin; in this case the 
ordinary regularity of the deposition of the sediment is 
interfered with by currents in the water, inducing a similar 
structure to that so generally noticeable in rocks that have 
been formed by the agency of the wind. 
From what has been already noticed it will be at once 
understood that as the sand dunes increase in size they must 
necessarily cover a greater area of country. The sand of 
these regions is ever on the move, and so rapid has been its 
progress in some parts of the world, our own colony included, . 
that it has been absolutely necessary to take steps to prevent 
its onward march, for if not prevented it would soon convert 
the most fertile soil into a barren waste of sand. The French 
coast along the Bay of Biscay was at one time very seriously 
affected by the onward movement of the dunes. Large areas 
of good land were rendered useless, and whole parishes and 
towns were completely obliterated. In that part of the 
world the rate of movement is recorded as 164 feet per 
annum, while in Denmark it is said to reach as much as 
24 feet per annum. The method adopted by the French to 
stop these inroads was the planting of pinetrees, and not only 
did this prove successful in preventing further inroads, but it 
has proved the source of a large revenue to the people, not 
only in the extraction of turpentine, but also in the use of 
the timber. ; 
In the early days the now sandy tract to the west of 
Belfast was clothed with Banksias (honeysuckles) and 
Casuarinc (sheoaks), but when the district became more 
populous, the timber gradually disappeared and left nothing 
to prevent the encroachment of the sand. At Warrnambool 
it was found necessary to take steps to put a stop to the 
serious encroachment of sand in that district. Baron Sir F. 
von Mueller was applied to for his advice in the dilemma, . 
