Effects of geology in the Lake District

On a grander scale the geology has had one final profound effect on the present landscape of the Hotels lake district. After the rocks were formed they were subjected to intense pressure caused by earth movements. Occasionally the rocks were folded but more often they were subject to faulting and associated shattering, with the result that linear belts of weakened strata were formed.

In time these belts were exploited by the various forces of erosion so that today many of the well-known valleys and passes of the Lake District have been carved out along these lines of structural weakness, as, for example, parts of the Great Langdale Valley, already noted. The fault zones vary in direction but many of the major dislocations have a distinct north-south trend.

The result is that, although the drainage pattern is broadly radial in plan, the more dominant elements are north-south. One major zone of shattered rocks runs from the head of Coniston Water across the col of Holme Fell and then continues into the lower end of Little Langdale, across the col of Red Bank to Grasmere. Its north¬ward continuation from here is along the line ofDunmail Raise, by Thirl¬mere into the valley of Naddle Beck and possibly extending right into the Skiddaw massif by the Glenderaterra Valley.

For much of its length erosion has succeeded in removing the weakened rock and thus created either valleys or low cols across the fells. The zone forms the one major break in the east-west watershed of the Lake District. On a much reduced scale the gorge of the River Duddon near Seathwaite follows another of these shatter belts. The same relationship is apparent in the valleys of Trout beck, Kentmere and Long Sled dale which run deeply into the SouthEastern Fells. Although they do not break through the high country to the north they nevertheless form distinctive topo¬graphic elements in this littleknown corner of the Lake District. The presence of belts of shattered rock and their relationship to the drainage pattern must not be taken to imply that all the Lake District valleys owe their alignment and form to this process of development.

Clearly in many instances the more potent force of ice erosion has played a dominant role. But, even then, many of these faulted belts determined the lines along which the valley glaciers moved. The weakened rock also allowed the glaciers to bite deeply into the valley floor and thus create the hollows which later formed the lakes. These are, after all, the most distinc¬tive features of the whole landscape and certainly the one element which has given the area its regional designation.

Two decades were to pass before their true significance was realized. Follow¬ing studies of the glaciers and mountain scenery of the Alps, the glacial theory was evolved. In December 1850 the Reverend Professor Buckland, in an address to the Geological Society of London, drew attention to the abounding evidence in the Lake District for the former existence of glaciers. Not only did the ice scatter boulders of distinctive rocks, like Shap granite, far and wide an explana¬tion that would have satisfied Jonathan Otley but it also dumped great assem¬blages of rocks and gravels on the margins of the area. In this connection Buck¬land mentioned the group of moraines by the roadside near Eden Hall, four miles east of Penrith.