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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    observers were misled by the novel features of our superfi- cial formations, and in many instances mistook for results of glacial action what were in reality alluvial accumulations, most of them being those ancient deltas of mountain streams which are so often found where narrow side glens join the principal valleys. Amongst the contemporary observations of Sir Charles Lyell, two objects are cited, which answer so entirely to the character of ancient terminal moraines that I cannot doubt their being of that character. They occur in the small ele- vated valleys on the skirts of the Grampians, which contain the Lochs Whorral and Brandy. Loch Brandy, says Sir Charles, is surrounded on three sides by lofty precipices of gneiss, while on the south it is bounded only by an enormous accumulation of sand, mud, and fragments of rocks, evidently derived from the cliffs which overhang the lake on the east, north, and west. We only can account for an accumula- tion of such a kind in such a position by supposing the action of a small local glacier. The two lochs are 1500 feet above the sea. Professor E-amsay has lately discovered lakes in North Wales formed by dams which he believes to be ancient moraines; and Mr Darwin has described similar objects as occurring in South America. Professor J. D. Forbes's Observations on the Cuchullin Hills, published in 1845, included descriptions of the general glacial phenomena of that district, which are certainly of a most striking character, the whole central valley, in which Loch Coruisk lies, being shaven bare and striated, with a vast number of blocks scattered over the surface, many of them in situations where ice alone could have placed them. Yet it is remarkable that no true moraine exists in this glen; that is to say, no train or ridge of the rough detrital matter marking the sides or skirts of an ancient glacier. Professor Forbes describes one true and unmistakeable moraine as forming an elongated semi-oval'' round the mouth of a deep corry on the outside (westward) of the Cuchullin group. He also adverts, in less confident terms, to something of the same kind at the mouth of the Corry-na-briech,—a short ab- ruj)t valley, likewise looking outwards to the north west,—