H. D. ROGERS.--On the Parallel Roads of Glen Roy. Royal Inst.
Proceedings, 1861, vol. iii. p. 341.

THOMAS F. JAMIESON.--On the Parallel Roads of Glen Roy, and their
Place in the History of the Glacial Period. Quart. Journal Geol.
Soc. 1863, vol. xix. p. 235.

SIR CHARLES LYELL.--Antiquity of Man. 1863, p. 253.

REV. R. B. WATSON.--On the Marine Origin of the Parallel Roads of Glen
Roy. Quart. Journ. Geol. Soc. 1865, vol. xxii. p. 9.

SIR JOHN LUBBOCK.--On the Parallel Roads of Glen Roy. Quart. Journ.
Geol. Soc. 1867, vol. xxiv. p. 83.

CHARLES BABBAGE.--Observations on the Parallel Roads of Glen Roy.
Quart. Journ. Geol. Soc. 1868, vol. xxiv. p. 273.

JAMES NICOL.--On the Origin of the Parallel Roads of Glen Roy. 1869.
Geol. Soc. Journal, vol. xxv. p. 282.

JAMES NICOL.--How the Parallel Roads of Glen Roy were formed. 1872.
Geol. Soc. Journal, vol. xxviii. p. 237.

MAJOR-GENERAL SIR HENRY JAMES, R.E.--Notes on the Parallel Roads of
Lochaber. 4to. 1874.

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IX. ALPINE SCULPTURE.

1864.

TO account for the conformation of the Alps, two hypotheses have been
advanced, which may be respectively named the hypothesis of fracture
and the hypothesis of erosion. The former assumes that the forces by
which the mountains were elevated produced fissures in the earth's
crust, and that the valleys of the Alps are the tracks of these
fissures; while the latter maintains that the valleys have been cut
out by the action of ice and water, the mountains themselves being the
residual forms of this grand sculpture. I had heard the Via Mala
cited as a conspicuous illustration of the fissure theory--the
profound chasm thus named, and through which the Hinter-Rhein now
flows, could, it was alleged, be nothing else than a crack in the
earth's crust. To the Via Mala I therefore went in 1864 to instruct
myself upon the point in question.

The gorge commences about a quarter of an hour above Tusis; and, on
entering it, the first impression certainly is that it must be a
fissure. This conclusion in my case was modified as I advanced. Some
distance up the gorge I found upon the slopes to my right quantities
of rolled stones, evidently rounded by water-action. Still further
up, and just before reaching the first bridge which spans the chasm, I
found more rolled stones, associated with sand and gravel. Through
this mass of detritus, fortunately, a vertical cutting had been made,
which exhibited a secti