Loire Valley (wine) a variety of limestone with excellent drainage that is known as tuffeau which is the same material used to build many of the famous Loire Valley Châteaux. The area around Chinon, Bourgueil and Saint-Nicolas-de-Bourgueil produces the majority of the Loire Valley's red wine based on the Cabernet franc grape—known in this areas as "Breton". The wines of the Chinon area are the softest and rich expression of the grape while the Bourgueil area produces more tannic and firm wines. The St-Nicolas-de-Bourgueil area produces the lightest colored wines. In the 19th century, the wines of the Chinon area were compared favorably
Loire Nevers, La Charité-sur-Loire, Cosne-Cours-sur-Loire, Cher: Sancerre, Loiret: Briare, Gien, Orléans, Loir-et-Cher: Blois, Indre-et-Loire: Amboise, Tours, Maine-et-Loire: Montsoreau, Saumur, Loire-Atlantique: Ancenis, Nantes, Saint-Nazaire. The Loire Valley in the Loire river basin, is a stretch in the western reach of the river starting with Orléans and terminating at Nantes, short of the Loire estuary and the Atlantic Ocean. The tidal stretch of the river extends to a length of and a width of , which has oil refineries, the port of Saint-Nazaire and of wetland whose formation is dated to 7500 BC (caused by inundation by sea waters on the northern bank