region, northwestern France. It stretches southwest of Paris toward the Forêt d'Orléans. One of the great traditional granaries of France, Beauce is a flat, fertile, treeless limestone plain that was once planted mainly with wheat and sugar beets. Maize (corn) was introduced in the 1950s and is now cultivated along with wheat and barley. Petit Beauce is an area of similar characteristics between the Loir (Loir River) and Loire (Loire River) rivers to the north of Blois. Agriculture in Beauce is highly productive. In recent years problems of overproduction and pollution of the water table have diminished interest in the exclusive cultivation of cereals. Production has been diversified to include rape seed, sugar beets, potatoes, vegetables (for the canning and frozen food industries), and pulses. The use of fertilizers is now strictly controlled, and mustard is sown to absorb excess nitrates. The church spires, grain silos, and water towers of the market towns thrust vividly out of the unrelieved flatness. Chartres, Châteaudun, Étampes, and Pithiviers are the main towns, and all have agricultural markets.