On glacial phenomena in Scotland and parts of England / by Robert Chambers.

Date:
1853
Catalogue details

Licence: Public Domain Mark

Credit: On glacial phenomena in Scotland and parts of England / by Robert Chambers. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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    feet long by fifteen broad, is laid bare by the removal of a coarse brown detritus containing boulders. It presents four bosses, side by side, in the direction of the length, and the whole is beautifully polished, with finely-marked striation across the planes of stratification, being in the direction of N. 46° W., [Mr Bryce says N. 34° W.,] thus pointing to- wards the eminence forming the west side of the upper and more mountainous portion of the Kent valley. A detritus of half-worn blocks mixed up with a brown mass of clay and sand, precisely resembling the moraine matter left at the sides and extremities of existing glaciers, is deposited in various parts of the Lake valleys, in immediate contact with the polished surfaces, and generally in the lee of emi- nences. It is generally where such matter has been excavat- ed for the making and repairing of roads, that we find the best examples of polished surfaces, the detritus having served as a complete protection to the vitreous polish left by the abrading agent. As far as I have observed, the superficial matters do not anywhere, in the central parts of the Lake District, present the peculiar forms of either lateral or termi- nal moraines, except in one instance, in the Thirlmere valley, near its head at Dunmail Raise. There, in the angle be- tween a side valley and the principal one, we find a long ridge of rough detritus with many large blocks, extending down the hill-face. An inexperienced observer would be at a loss to understand the relations in which such an object could stand towards any imaginable glacier hereabouts ; but one who has seen the moraines of the Glacier des Bois and the Glacier d'Argentiere iu the Chamouni valley, would quickly perceive that this, in reality, is the right lateral mo- raine of the glacier which issued at this place into the Thirl- mere valley, from one of the high glens which ascend into the mountain chain of Bowfell. Mr Maclaren's moraine in Glen Messan has been surmised as an object of precisely .similar history. Not far from the moraine just described, on the summit called Dunmail Raise, which is a valley of passage between t wo ordinary valleys, there is a great mass of detrital matter, through which the infant rills of the district have made deep
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