Brittany, the extreme Western promontory of the North of France, comprises the five departments of CÔtes-du-Nord, Ille-et-Vilaine, FinistÈre, Morbihan, and Loire-InfÉrieure. It is distinguished into Upper and Lower Brittany. In the former the French language is spoken, in the latter the Breton, and French is an acquired tongue. The back-bone of Upper Brittany is the chain of the Menez that runs from East to West, and then branches, forming on the North the Montagnes d'ArrÉe, and on the South, the Montagnes Noires. The system may be likened to a hay-fork or a pair of tongs, where the prongs of the fork form the above-named ranges. The whole rests on an elevated plateau that slopes to the sea North and West, and on the South dies down into the plain of the Vilaine and the Loire. On the North this plateau is seamed by the rivers that have cut narrow valleys and ravines through which they make their way to the sea. Such are the Rance, the Gouet, the riviÈre de Morlaix, with the result that there is no coast-road, The mountain range is nowhere high, and rarely reaches a thousand feet. The highest point is the Mont Saint Michel which attains to slightly over 1200 ft. The freshman arriving at Cambridge asked where was the Gogmagog range, and was told that he might see it when an intervening cart got out of the way. Owing to the ridges rising out of an elevated plateau, they are almost as insignificant as the Gogmagogs. However, the Menez-hom most nearly attains to the dignity of a mountain, as it stands above the Bay of Douarnenez, reaches however only to 990 ft. Along the Western confines of the department of Ille-et-Vilaine, the Menez spreads out into high tableland sown with lakelets acting as feeders to the Vilaine. The Monts d'ArrÉe, starting from the Coat-an-Noz in CÔtes-du-Nord, extend to the peninsula of Crozon, they attain their highest point at the Mont S. Michel, and decline as they approach the sea. They rarely rise 300 ft. above the tableland on which they are planted, and this prevents them from having an imposing appearance. The Montagnes Noires flank the central plain on the South. Their maximum height is 1050 In the Morbihan, the Lande de Lanvaux, running from W. to N.E., extends 50 kilometres, and rises to the height of from 240 to 320 ft. between the basins of the Claye and the Arz which unite at Redon to feed the Vilaine. The North coast of Brittany is eaten into bays from which the sea retreats to considerable distances, and is fringed with reefs and islands. It is a favourite resort of Parisians, throughout its stretch, from Dinard to Plestin. The West of this peninsula is torn into shreds of promontories with deep inlets between them. The promontories of S. Mathieu, Crozon, Sizun, and Penmarch are bald, but bold. Below the point of Penmarch the coast rapidly trends S.E. and alters in character; it loses its bleak desolation and ragged rocky nature, and forms landlocked seas, as those of Belz and the Morbihan; and the rocks make way for sand-dunes. The island chain that constitutes a natural breakwater to the bay of Quiberon is the wreckage of the barrier of another inland sea, broken up by the Atlantic surges. South of the mouth of the Loire the island of Noirmoutier stretches almost sufficiently far out to enclose another. The plateau formation of the country is not conducive to beauty, and its lovely sites must be sought in the valleys, and its wildest scenes on the coast. The deep cleft ravine of the Rance, The promontories of Crozon and Sizun till of late years were bare and untilled, and heath-grown; but the use of sardine heads as manure has given a great impetus to agriculture, and the demand for fir balks for the South Welsh mines has caused the planting of vast tracts with the Austrian pine. The geological structure of Brittany is simple. It consists of an immense upheaval of granite through beds of Silurian and Cambrian schist. Rare deposits of lime occur in the folds of these beds. Dykes of quartz and diorite have traversed the schist and granite, and the face of the country is spotted with eruptions of igneous matter. It is as though the crust had been full of blowholes through which the molten diorite had rushed to the surface. The presence of quartz or diorite in the neighbourhood can always be recognised by the employment of one or the other to metal the roads. The granite extends from the bay of Mont Saint Michel to the extreme point of FinistÈre and reappears in the isles beyond; it is interrupted only here and there by the sedimentary beds. The ChÂteaulin district, however, and the basin between the prongs of the mountain fork, are all of Cambrian and Silurian beds. But from the Pointe du Raz the granite extends almost uninterruptedly to the Rhone. The Brittany granite is for the most part fine grained and soft, so that it lends itself easily to be carved, and has been freely employed in churches and secular buildings from the 11th century. But it is readily corroded by the weather, and this has given to denuded surfaces a smooth and rounded shape, and has taken the angles off exposed masses that form tors, and has occasioned the fall of many into utter ruin. A band of syenite runs from near Lamballe to Cap FrÉhel, where it forms magnificent cliffs. Syenite again comes to the surface at TrÉgastel and on the coast north of Morlaix. The Monts d'ArrÉe are of Cambrian schist and furnish slates here and there of good quality. Taking a section across the inner basin, the granite is quitted at PlounÉour, then the ridge of Cambrian schist is reached, after crossing the culminating point of S. Michel, which is of Cambrian sandstone; when we reach S. Herbot we are on Silurian beds. Continuing our course south, the sandstone makes way for slaty schists, and to this succeeds the grauwacke of Brasparts. The Montagnes Noires belong to the Silurian system. The Kersanton stone, so extensively employed for figure and foliage sculpture in Lower Brittany, is an amphibolite with mica freely comminuted and distributed through the substance. It is very dark in colour, and hardens with exposure. It comes from quarries to the south of the Rade de Brest. An interesting deposit is the tertiary limestone of S. Juvat beside the Rance. It is of no A mineralogical curiosity is the staurotides found at Baud, Scaer, and in various places about the Blavet. The peasants attach a superstitious value to them as marked with the cross, and in some they affect to recognise the nails. They are often sold on stalls at a Pardon. They are formed by trapdykes that have penetrated the schist, and fused and run together some of its constituents, which have afterwards crystallised, sometimes as parallel prisms, at others as set transversely forming the ordinary or the S. Andrew's Cross. |