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VI.—On the Dispersion of Criffell, Granite and Caldbeck Porphyry over the Plain of Cumberland1

Published online by Cambridge University Press:  01 May 2009

Extract

The following is a very brief statement of the results of nearly two months' observations on the granitic and porphyritic drift of the north and north-west of Cumberland.

Type
Original Articles
Copyright
Copyright © Cambridge University Press 1870

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Footnotes

1

For Kistoneand Kirston, read Kirkstone, in mylast article (Geol. Mao. for Oct.).

References

page 564 note 2 The so-called surface-blocks are those which have escaped being buried, or which have been disinterred by farmers. The boulders of granite and other rocks are found principally in the lower Boulder-clay, but they are not absent from the upper.

page 564 note 3 Nearly all the boulders are more or less rounded.

page 565 note 1 Accompanying the granitic drift, especially on the sea-coast, there are numerous pebbles, and occasional boulders of dark, hard, fine-grained whinstone, which would appear to have come from the Scottish side of the Solway Firth, where, in many places, it is the prevailing rock.

page 566 note 1 Mr. Eccleston, of the Fawcett Schools, Carlisle, informs me that he has found boulders of Criffell granite as far east as Gillsland, and as far south as Whit beck, near Bootle. If I recollect rightly, there are numbers of them in the West-Midland counties.

page 566 note 2 I have to thank the Messrs. Newall, of the Craig Nair (Dalbeattie) Granite Works, for corroborating my views, founded on Professor Sedgwick's theory, relative to the derivation of the Cumberland boulders.

page 567 note 1 I have lately found that limestone drift (including a split-block 10 feet in diameter and of unknown thickness) from the N. or W. has been left on the western slope of Dent Hill, near Cleator, by a current which, at a greater or less angle, must hare been crossed by the above-mentioned syenitic and porphyritic drift from Enner-dale, which covers nearly the whole of Dent Hill (Skiddaw Slate) up to the summit, near to which, at 1,100 feet above the sea, there is a boulder, 8x8x5 feet, called Samson's Cobble, or the Finger Stone, consisting of rock midway between porphyry and syenite.

page 567 note 2 Here it forms a plateau, and rests partly on rock and partly on the reddish-brown clay.

page 568 note 1 In Professor Harkness' paper on Shapfell Blocks in the Quart. Journ. Geol. Soc. for November, it is stated that Shapfell granite does not occur in the Boulder-clay of the Eden valley, though Criffell granite is found in this clay. The Eden yalley clay may hare nearly ceased to accumulate before the high-level granite of Wasdale Crag began to be dispersed, and imbedded in the pinel or Boulder-clay of the mountains, in which it is associated with polished and striated stones and boulders. (See article on Shapfell Soulders, Geol,. Mag., Aug., 1870.)