JP's reference was clear, but seems to be different from the case cited by W. Hopkins about erratic conglomerate boulders. Asks for more details on the latter. CD does not think much of Hopkins' paper ["Elevation and denudation of the district of the lakes of Cumberland and Westmorland", Q. J. Geol. Soc. Lond. 4 (1848): 70–98].
Down Farnborough Kent
My dear Phillips
Will you forgive me troubling you once again. Your reference
guided me to the exact case in point; but the fact referred to by
I cannot find Stainmoor in such maps as I have, & as you will perceive, I am in
a complete jumble on the subject. Are the conglomerate boulders rounded or quite
angular? Hopkins throws from some reflected quarter some
doubt about the identification of the conglomerate; if you have no doubt, I
I cannot say that I think much of this paper of Hopkins'
Believe me | Very sincerely Yours | C. Darwin
Can you remember whether the highest Slate-boulders were more worn, than those transported to a lesser height?
- f1 1162.f1Phillips had apparently sent CD a reference to Phillips 1835. See letter to John Phillips, [12? March 1848], in which CD stated he had found the reference he wanted in Phillips 1837–9.
- f2 1162.f2Hopkins 1848, originally read in 1842, was published as a postponed paper in the Quarterly Journal of the Geological Society of London.
- f3 1162.f3In ‘On the transportal of erratic boulders’ (Collected papers 1: 218), CD stated the case as follows:
The conglomerate alluded to by Mr. Hopkins has been transported from the bottom of the valley of the Eden, where the rock lies in situ at the height of 500 feet above the level of the sea, to and over the pass of Stainmoor at the height of 1400 feet: therefore the boulders now lie 900 feet above their original position.
- f4 1162.f4Boulders transported by icebergs would be angular, whereas if they were transported by coast-ice, as CD believed, they would be worn from repeated exposure to shore-line sea action (Collected papers 1: 221).
- f5 1162.f5CD's question evidently was not answered by Phillips, because it reappeared unaltered in his paper (Collected papers 1: 223):
It would be interesting to ascertain whether those [slate] boulders which now stand highest above the parent rock are more worn than those at a lower level, which latter I believe to have been dropped during the long-continued buoying-up process.