158 
THE MEDITERRANEAN NATURALIST 
basins are restricted in size. In such districts a 
large proportion of the denudation to which the 
surface contour of the district owes its diversified 
character, is to be attributed to the slow and 
intermittent, though powerful, agency of this wind. 
It is along the escarpments of the hills and 
valleys, and in the cliff exposures that have a 
south-easterly aspect, that its powers of erosion 
are to be studied to the best advantage. 
The flat-topped conical hills that form such a 
distinguishing feature in Malta and Gozitan sce- 
nery, owe their origin, in a great measure, to its 
influence. The Globigerina Limestone, the fourth 
bed from the top, forms the base of all of these 
hills, and on account of its homogeneity and 
softness of texture, it readily disintegrates before 
the rapid alternations of dryness and humidity 
that are the usual concomitants of the Sirocco. 
This bed may be traced from the bottoms of all 
of the valleys in the Binjemma and the Gozitan 
plateaux, falling bad?, in long-draw swellings and 
gentle undulations; and is covered with a rich and 
productive soil, in which the crimson sulla (clover), 
and the golden rye for which the islands are noted, 
grow luxuriantly. 
Capping this bed, and still Idling back in softly 
rounded masses are the dun-coloured marls, the 
taluses of which often descend the slopes to 
distances that are double, and even treble the real 
thickness of the bed. These marl outcrops are a 
characteristic of Maltese hill scenery. They owe 
their origin to the percolation of water through 
the upper beds, whereby the marl is rendered 
sodden, and then, being more susceptible to the 
weight of the superincumbent rock than when dry, 
it is pressed from out the strata, and precipitated 
down the hill-sides. 
The bases of the hills, therefore, have a cloak of 
marl which effectually protects them from aerial 
waste, while the upper portions, being without this 
protective influence, rapidly waste away before the 
humid winds, and thus the slopes of the valleys 
are seldom precipitous, and the isolated hills 
assume a distinctly conical form. 
The hills and plateaux are in this way shielded 
below by their own ruins, while the wasting away 
of the upper portions causes them to gradually as 
sume the tapering shape with which the student 
of Maltese scenery is so familiar. 
Unlike the Globigerina Limestone, the Upper 
Coralline rock is not equally susceptible to the 
influences of this wind. But certain portions of 
the strata, situated in the middle of the formation, 
weather much faster than do the layers either 
above it or below' it. 
In the majority of cases this formation is found 
capping the hills of both islands, and forming 
tablelands, the sides of which are bounded by 
precipitous cliffs that attain a height which is 
dependent upon the local thickness of the bed. 
It also forms the surface deposits of several 
undulating plains, and it frequently occurs as 
shapeless hummock-like masses. These diversities 
of form are due in a measure to the unequal wmste 
that the rock undergoes, as its mineralogical com- 
position varies considerably, some parts of the 
strata being so hard as to be capable of withstand- 
ing the combined action of the atmosphere for 
centuries, while other portions readily disintegrate 
on exposure. 
It is to this unequal action that the formation 
owes the craggy contour of its cliff outlines; and 
it is this that causes it to offer such marked 
contrasts to the gentler undulations of the softer 
beds beneath. It is from this formation, too, that 
the rock boulders that strew the slopes and beds 
of the valleys of the islands, are derived. 
The action of the sirocco and the rain upon the 
sand-bed that serves as the foundations of the 
formation, by gradually wearing it away, deprives 
the upper bed of its support, and causes the cliffs 
to break away in cyclopean masses, and to strew 
the slopes of the hills and valleys •with their de- 
bris; while other masses are detached and are tilted 
so perilously out of the perpendicular that they 
appear — 
“As if an infant’s touch could urge 
Its headlong passage down the verge.” 
Such are a few of the effects that this powerful 
eroding agent is, in part, accountable for; but it 
has, of course, been assisted in its work by 'other 
and equally powerful auxiliaries, without whose 
co-operation its efforts could not have been so 
effective. The main features of the country, the 
hills, valleys, and gorges have had their direction 
and extent largely influenced by the lay of the 
strata; while the minor ones, such as the honey- 
combed and fretted appearances presented by the 
