ow watersheds, Mr. Milne only gives half of my
explanation. Please read page 65 of my paper. (520/3. "Observations
on the Parallel Roads of Glen Roy, and of other Parts of Lochaber in
Scotland, with an Attempt to Prove that they are of Marine Origin."
"Phil. Trans. R. Soc." 1839, page 39. [Read February 7th, 1839.]) I
allude only to the head of Glen Roy and Kilfinnin as silted up. I did
not know Mukkul Pass; and Glen Roy was so much covered up that I did not
search it well, as I was not able to walk very well. It has been an old
conjectural belief of mine that a rising surface becomes stationary,
not suddenly, but by the movement becoming very slow. Now, this would
greatly aid the tidal currents cutting down the passes between the
mountains just before, and to the level of, the stationary periods.
The currents in the fiords in T. del Fuego in a narrow crooked part are
often most violent; in other parts they seem to silt up.

Shall you do any levelling? I believe all the levelling has been
[done] in Glen Roy, nearly parallel to the Great Glen of Scotland. For
inequalities of elevation, the valley of the Spean, at right angles to
the apparent axes of elevation, would be the one to examine. If you go
to the head of Glen Roy, attend to the apparent shelf above the highest
one in Glen Roy, lying on the south side of Loch Spey, and therefore
beyond the watershed of Glen Roy. It would be a crucial case. I was
too unwell on that day to examine it carefully, and I had no levelling
instruments. Do these fragments coincide in level with Glen Gluoy shelf?

MacCulloch talks of one in Glen Turret above the shelf. I could not see
it. These would be important discoveries. But I will write no more, and
pray your forgiveness for this long, ill-written outpouring. I am very
glad you keep to your subject of the terraces. I have lately observed
that you have one great authority (C. Prevost), [not] that authority
signifies a [farthing?] on your side respecting your heretical and
damnable doctrine of the ocean falling. You see I am orthodox to the
burning pitch.

LETTER 521. TO D. MILNE-HOME. Down, [September] 20th, [1847].

I am much obliged by your note. I returned from London on Saturday, and
I found then your memoir (521/1. "On the Parallel Roads of Lochaber,
with Remarks on the Change of Relative Levels of Sea and Land in
Scotland, and on the Detrital Deposits in that Country," "Trans. R.
Soc. Edinb." Volume XVI., page 395, 1849. [R