i? H. J. JOHNSTON-LAVIS ON THE GEOLOGY 
precipices or cascades, although usually dry,they are forsaken by these 
men for the soft and ashy paths only to be obtained on the higher 
ground. ‘The reason for this is the more obvious when it is remem- 
bered that boots are never worn, and all the methods of transport are 
human. The sapling poles are tied into a bundle, varying in number 
according to their weight, by their lower and thick ends, which part 
is supported on the back and shoulders in a stooping position, the 
knotty and branched and pointed ends dragging along the ground 
behind. These bundles act as so many harrows ploughing up the 
ground and sweeping it down the steep incline, aided at the same 
time by the feet of the porter, producing very evident effects. The 
same with the faggots of brushwood composed of chestnut and broom 
bushes, which, in bunches of six tied together, hauled along behind 
the transporter, play the part of so many brooms. 
It might appear that the above agencies were of the most feeble 
effect. The great luxuriance of the vegetation of the mountain, 
which is completely stripped during the summer months when these 
soft incoherent rocks are easily reduced to fine light dust or small 
fragments, must, however, be remembered. It is really astonishing 
to see the progress made in the course of such a period as three 
years, during which I have had many of the paths under observation. 
When we see the disturbance produced by a single passage of one of 
these loads, we have no difficulty in imagining the effect of many 
hundreds during the year. 
Of course these human denuding agencies are aided by rainfall 
and other natural ones. Water, however, can do little, as these 
cupe occupy the centre of the ridge, where the surface slopes 
away, instead of towards the depression, and therefore the rain does 
not fall into these gorges, which are in reality principally the cutting 
downwards of paths made by man. From receiving no extraneous 
water laterally, their sides remain nearly perpendicular. Two 
irregular examples may be seen in section, in PI. II. fig. 2, on the high 
ground between the Vallone di Pollena and the two large collateral 
valloni. When, as happens occasionally, the valleys have at a cer- 
tain depth a loose incoherent breccia entering into the composition 
of their sides, this by simple gravity crumbles away, leaving the 
upper more resistent deposits above unsupported, which fall in 
blocks, are reduced to dust, and carried down by the various methods 
we have mentioned. ‘The result is, the walls of the path become 
inclined, and catch more rain, which soon gives to the cupa the charac- 
ters of a small valley. Various examples of these may be seen on 
the high ground flanking the Valloni Cancherone, Grande, di Cas- 
tello, and many others. Sometimes aqueous denudation has gained 
such a hold that the hard lavas are reached and eroded, but usually 
the cupe join a great valley at the upper surface of the lava-beds or 
at the branching of the Y, so that their drainage falls over the side 
as a cascade. 
There are many valleys that in all probability owe their primary 
origin to a simple footpath, such as the Vallone St. Patrizio and 
many others of its type. 
