Ille et vilaine


The department of Ille-et-Vilaine belongs to the Brittany area. It is bordering on the departments of the English Channel, Mayenne, Maine-et-Loire, the Loire-Atlantique, Morbihan and of Dimension-with Armor, and east bathes by the English Channel, its littoral pertaining to the Emerald dimension.

The Ille-et-Vilaine extends on 6 775 km2. It is located between the meridian lines 1? and 2? 20 ' West and the parallels 47? 40 ' and 48? 40 ' North. It is about the Breton department least maritime since its littoral, opening on the English Channel, is only of 70 km.

The Ille-et-Vilaine east locates on a topographic depression. It east protects from flows of west by the heights of the Armorican Solid mass and the continental influences in the east with the hills Normans and of Maine. By its geology, the major part of the septentrional half belongs to the north-Armorican field, other half raising the center-Armorican field, only a small portion around Redon being included/understood in the south-Armorican field.

Indeed, the central part and littoral of the department is of low altitude, generally lower has 50 bills of quantities in the coastal strip and the valleys and less than 100 bills of quantities almost everywhere. It is only in limits Western and Eastern that are more raised reliefs:

  • in the west, the hills of Becherel (190 bills of quantities) and the drill of Paimpont or the Ille-et-Vilaine culminates has 256 bills of quantities;
  • in the east, Coglais and country of Ferns (251 bills of quantities with the Vault-Janson).

Basins: hollow by erosion in the tender schists, they develop principal rivers on both sides:

  • in north, basin of the affluents of Rancid and basins of Couesnon;
  • in the center and the south, basins of Unpleasant of which most important, that of Rennes.


  • in the south in the form of rock Armorican sandstone or hard schist bars made up, direct west-north-west - east-south-east, separated by broad valleys or run affluents of the Unpleasant one;
  • in north in broader bands and more uniforms made up of hard schists or granite alternating with the basins.

The maritime areas including/understanding is of Cancale, the marshes of Fraud and the Saint-Michel mount, and with the west a plate of crystalline rocks deeply notch by the Rancid one.

As regards pedology and botany, the basement is often impermeable because of presence of granitic rocks. So that very little ground water is found and only surface water is found. The rivers see their flow varying according to oceanic flows bringing the rain. If one long period ago without precipitations, the Ille-et-Vilaine can suffer from the dryness. But an important pluviometric contribution can cause floods because the grounds can be water throats.

Agriculture is mainly basee on the breeding, which makes of it the first dairy department of France. That has as consequences, an adaptation of agriculture with cultures orientees for the animal feeds with corn, but, plants fourrageres and meadows.

Except these spaces anthropises, there remains natural spaces like the moor on the plates in the south and cliffs of the littoral, approximately 60 000 hectares of forest (drill of Paimpont, Ferns, of Rennes, of Liffre, Teillay, etc); wetlands of the department.

Source: Wikipedia.

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