never to trust in science to the principle of exclusion." (517/14. "Life
and Letters," I., page 69.)


LETTER 517. TO C. LYELL.
[March 9th, 1841.]

I have just received your note. It is the greatest pleasure to me to write
or talk Geology with you...

I think I have thought over the whole case without prejudice, and remain
firmly convinced they [the parallel roads] are marine beaches. My
principal reason for doing so is what I have urged in my paper (517/15.
"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.), the buttress-like
accumulations of stratified shingle on sides of valley, especially those
just below the lowest shelf in Spean Valley.

2nd. I can hardly conceive the extension of the glaciers in front of the
valley of Kilfinnin, where I found a new road--where the sides of Great
Glen are not very lofty.

3rd. The flat watersheds which I describe in places where there are no
roads, as well as those connected with "roads." These remain unexplained.

I might continue to add many other such reasons, all of which, however, I
daresay would appear trifling to any one who had not visited the district.
With respect to equable elevation, it cannot be a valid objection to any
one who thinks of Scandinavia or the Pampas. With respect to the glacier