ing.

[Illustration: J. M. W. Turner. J. Ruskin.
37. Crests of the Slaty Crystallines.]

[Illustration: FIG. 70.]

1. A B and associated lines _a b_, _a b_, &c., over the whole plate.
True beds or cleavage beds (_g h_ in Aiguille Bouchard, Plate
+34+); here, observe, closing in retiring perspective with
exquisite subtlety, and giving the great unity of radiation to
the whole mass.

2. D E and associated lines _d e_, _d e_, over all the plate. Cross
cleavage, the second in Aiguille Bouchard; straight and sharp.
Forming here the series of crests at B and D.

3. _r s_, _r s_. Counter-crests, closely corresponding to
counter-fracture, the third in Aiguille Bouchard.

4. _m n_, _m n_, &c., over the whole. Writhing aqueous lines falling
gradually into the cleavages. Fifth group in Aiguille Bouchard.
The starchy cleavage is not seen here, it being not generally
characteristic of the crests, and present in the Bouchard only
accidentally.

5. _x x x_. Sinuous lines worn by the water, indicative of some softness
or flaws in the rock; these probably the occasion or consequence
of the formation of the great precipice or brow on the right. We
shall have more to say of them in Chap. XVII.

[Illustration: FIG. 71.]

6. _g f_, _g f_, &c. Broad aqueous or glacial curvatures. The sixth
group in Aiguille Bouchard.

7. _k l_, _k l_. Concave curves wrought by the descending avalanche;
peculiar, of course, to this spot.

8. _i h_, _i h_. Secondary convex curves, glacial or aqueous,
corresponding to _g f_, but wrought into the minor secondary
ravine. This secondary ravine is associated with the opponent
aiguillesque masses _r s_; and the cause of the break or gap
between these and the crests B D is indicated by the elbow or
joint of nearer rock, M, where the distortion of the beds or
change in their nature first takes place. Turner's idea of the
structure of the whole mass has evidently been that in section it
was as in Fig. 71, snapped asunder by elevation, with a nucleus
at M, which, allowing for perspective, is precisely on the line
of the chasm running in the direction of the arrow; but he gives
more of the curved aiguillesque fracture to these upper crests,
which are greater in elevation (and we saw, someti