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I.—On the Origin of the Drifts, so-called Moraines, and Glaciated Rock-Surfaces of the Lake District1

Published online by Cambridge University Press:  01 May 2009

D. Mackintosh
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Extract

The Lake District differs from other parts of England in the comparative absence of table-lands or broad upland plateaux. The original mountain-masses have in most parts been eaten into by denudation to such a depth as to leave only a series of narrow ridges or edges which act as buttresses to small peaks. When the pedestrian has climbed up from the inner end of one profound excavation, he finds himself on the brink of another. The larger valleys are deepest at their inner ends, and shallow out and narrow off towards their entrances. Their floors fall so slightly outwards that were the outlet stream-channels to be filled up, the valleys would be converted into troughs. In most instances their mouths are confronted by higher ground, and this is sometimes so strikingly the case that in approaching a valley from the surrounding belt of Carboniferous strata, you find yourself going down instead of up among the mountains. The highest ground is not in the centre, but irregularly surrounds a comparatively depressed area about ten miles in average diameter. Such a configuration of country could not have been the best adapted for accommodating a quantity of snow at a high level sufficient to send very large “tongues of ice” along the radiating valleys.

Type
Original Articles
Information
Geological Magazine , Volume 7 , Issue 76 , October 1870 , pp. 445 - 460
Copyright
Copyright © Cambridge University Press 1870

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Footnotes

1

In the article on Shapfell Boulders (Aug., 1870, Vol. VII.), p. 350, line 9 from foot of page, for Stainmore, read Stainmoor; same page, line 13 from foot, the l in Kendal was omitted.

References

page 446 note 1 Many, if not most of these mounds exist, because the drift of which they consist was directly, or indirectly, arrested by a projecting boss of rock.

page 446 note 2 The regularly flat or curvilinear surface of drift-deposits is owing partly to deposition and partly to denudation. It could only have been left by the sea, as the effect of rain is to rut down the sides of the knolls and break up the plateaux, while rivers either make well-defined channels in the plateaux, or, by encroaching on the knolls, convert their slopes into cliffs.

page 447 note 1 The character and mode of occurrence of the blue clay of the N.W. of England, but especially of the West Riding of Yorkshire, (see Paper on the West Riding Drifts in forthcoming Proceedings of the West Riding Geol. Soe., noticed in Geol. Mag. of last June,) suggests another question, namely, whether the submergence commenced before the arrival of a comparatively mild climate, followed by a second sub-glacial period. This, of course, supposes that the astronomical may have been sufficient to neutralize the geological causes of climatal revolutions.

page 447 note 2 These boulders are not merely surface-blocks, but are often deeply imbedded, and most numerous towards the base of the deposit.

page 447 note 3 Mr. Hull and Professor Ramsay both arrived at the conclusion that the two Boulder-clays of Lancashire were stratified. Mem. Lit. Phil. Soc., Manchester, for 1863–64.

page 448 note 1 See Scenery of England and Wales.

page 450 note 1 Scenery of England and Wales.

page 456 note 1 Mr. Ward's Lecture on Ice (Trübner & Co.).

page 459 note 1 This article has expanded to such unexpected dimensions, that a brief statement of the results of several weeks’ researches into the derivation and distribution of the granitic drift of West Cumberland must be reserved for a future number of the Geological Magazine.