196 Ruskin—WNotes on the Denudation of the Alps. 
over leagues. But I call every cleavage ‘ native’ which has 
been produced by contraction, expansion, segregation, or crystal- 
lization, whatever the space over which the rock may be moved 
by its structural change; and I only call a cleavage ‘ passive’ 
which has been caused by a strain on the rock under external 
force. Practically, the two cleavages, or rather the two groups 
of cleavages, mingle with and modify each other; but the 
‘native’ cleavage is universal ;—the ‘ passive’ is local, and 
has more direct relations with the mountain-form. 
In the range, for instance, of which the Aiguille de Varens 
forms the salient point, of which the rough outline is given in 
the same plate, fig. 2, seen in front, and in fig. 4, seen in profile, 
the real beds dip in the direction a 4, fig. 4, bemg conspicuous 
in every aspect of the mountain in its profile: they are seen 
again on the opposite side of the valley (of Maglans) at ed. On 
the face of the mass, fig. 2, they are seen to be contorted and 
wrinkled, on the left reversed in complete zigzags;* but 
through all these a native cleavage developes itself in the 
direction ef, accompanied by an elaborate network of diagonal 
veining with calcareous spar. 
This cleavage directs the entire system of the descending 
streams, which, by help of it, cut the steps of precipice into 
oblique prisms, curved more and more steeply downwards, as 
the sweep of the torrent gains in power; so that, seen from a 
point a little farther to the right, the mountain seems composed 
of vast vertical beds, more or less curved in contour, fig. 3. 
But the face of the precipice itself is hewn into steps and walls, 
with intermediate slopes, by a grand vertical passive cleavage, 
gh, fig. 4, to which the direction and disposition of the entire 
Valley of Maglans are originally owing. 
And thus in any given mountain-mass, before we can touch 
the question of denudation, we have to determine the position 
it occupies in the wave-system of the country,—the connections 
of its cleavages with those of neighbouring masses,—and the 
probable points of maxima elevation which directed the original 
courses of glacier and stream. Then come the yet more intri- 
cate questions respecting the state of the materials at each 
successive elevation, and during the action of the successively 
destructive atmospheric influences. 
I have no pretension to state more than a few of the main 
facts bearing on such questions in the Savoy districts of the 
Lower Chalk, which I will endeavour to do briefly in one or 
two following papers. 
* This contortion is an important one, existing on both sides of the valley; but 
it is in reality farther to the left. I have crowded it in to complete the typical 
figure. 
