Comments on the discussion of erratic blocks in Journal of researches [pp. 619, 621–2].
of which a copy is in the Geol. Society Library is not quite expressed by what is said
at the bottom of this page; and certainly Jameson's notice is
P. 619 The shores of the Tertiary sea of the
Jura is shown in beautiful models of these mountains made by one of Agassiz'
pupils, of which one was made (Q
P 621 Agassiz describes most correctly the phenomena near Neuchatel, but they
did not seem to me sufficient to prove the arrangement in the order of sand, pebbles and
blocks to be a general fact. I would explain them by the familiar fact, of small bodies
when agitated with larger ones finding the bottom. They do not
correspond to the facts everywhere to be observed in the diluvial Hills of the north of
Scotland—there, pebbles, boulders and sand are mixed, or partially
interstratified with each other, and often exhibit the laminated appearance of the older
sandstones or the sand of the shore; and they sometimes contain large blocks which have
come from the west.—
P 622. I found a little north of Pettycur in Fifeshire, the sandstones having grooved
and polished surfaces exactly like the
limestone of Neuchatel, except that there the smooth way in which the
Neritinæ are cut across makes it more striking. The
grooves are in the same direction as on Corstorphine Hill, and the corners of the strata
are rounded off, and part of the upper has been removed, and the inferior is
polished. This I believe was not discovered previous to my
visit in Feb
The passage of the blocks in Scotland from the west; and the drift extending into all the valleys can hardly be explained by the theory of glaciers—or rather I do not see how it is to be applied to the cases with which I am most familiar.
- f1 559.f1Dated on the assumption that Malcolmson received and read the Journal of researches soon after he wrote his letter of 7 October 1839, in which he said that he was expecting it daily.
- f2 559.f2The notes refer to the pages in the Journal of researches in which CD states his theory of erratic boulders and discusses Agassiz's views of the glaciers and erratic boulders of Switzerland. The subject of Malcolmson's comment is CD's footnote on p. 617, in which he refers to p. 215 of an article by Jean de Charpentier in the Edinburgh New Philosophical Journal 21 (1836): 210–20. Robert Jameson was the editor of the Edinburgh New Philosophical Journal.
- f3 559.f3CD's explanation of the Jura blocks was based on the assumption that an arm of the sea once extended between the Jura and the Alps.
- f4 559.f4J. Anderson 1841.