Ruskin—WNotes on the Denudation of the Alps. 195 
that I never stay long in the breccia districts. But a few 
hours of study by the shores of the Reuss or Limmat are enough 
to show the general differences in aspect of compression be- 
tween metamorphic schists and conglomerates ; and the distinc- 
tion on a large scale is everywhere notable; but complicated 
by this fact, which I have not until lately ascertained positively, 
that through even the most contorted beds of the limestones 
there run strange, long, rectilinear cleavages, extending in | 
consistent slopes for leagues,—giving the mountain-mass, seen 
at right angles to their direction, an aspect of quite even stra- 
tification and elevation, with a strike entirely independent of 
its true beds and minor cleavages, and traversing them all. 
Putting these gigantic cleavages (of the origin of which, 
even if I could guess any reason, I would still say nothing so 
long as I could do no more than guess) for the present out of 
the question, the mass of the Savoy limestones forms a series 
of surges, retreating from the Alps, undulatory in two direc- 
tions at least, as at fig. 1, A, Pl VI., and traversed by fissures 
usually at right angles to the strike of the longitudinal surge. 
When that strike varies consistently at the same time, we may 
get conditions of radiant curve and fracture, B; and the undu- 
lations themselves are seldom simple, as at a, but either com- 
plicated by successive emergence of beds, b, or more frequently 
by successive faults, c, farther modified by denudation of upper 
beds, d, and, locally, by reversals of their entire series, e. 
All these complex phenomena will be produced by one con- 
sistent agency of elevatory or compressive force. Any num- 
ber of such tides of force may of course succeed each other at 
different epochs, each traversing the series of beds in new 
directions,—intersecting the forms already produced, and giving 
maxima and minima of elevation and depression where its own 
maxima and minima coincide with those resultant from previous 
forces. 
Now, by every such passage of force, a new series of cleav- 
ages is produced in the rocks, which I shall for the present 
call ‘ passive cleavages,’ as opposed to ‘native cleavages.’ I 
do not care about the names; anybody is welcome to give them 
what names they choose; but it is necessary to understand and 
accept the distinction. I call a cleavage ‘native’ which is 
produced by changes in the relation of the constituent particles 
of a rock while the mass of it is in repose. I call a cleavage 
‘passive’ which is produced by the motion of the entire mass 
under given pressures or strains. Only I do not call the 
mere contraction and expansion of the rock motion; though, 
m large formations, such changes in bulk may involve motion 
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