the Libroreau farm and the railroad, composed of Glauconite clay, used in iron ore, date back to the lower Cenomanian. This clay is also found around the alluvium along the river. Hydrology There is only one water course of consequence through the town: the Orne champagne. This is a direct tributary of the Sarthe. It is a small river, with an average rate of per second. It bypasses the town to the north and crosses the Souligné-Flacé road at the Gué Perroux bridge. This is where the communal washhouse of 1855 stood in 1956 (). Two small streams that flow through the town empty into the Orne champenoise at Étival-lès-le-Mans: Liboreau Creek (south-west of the town) () and the Beaumerie stream (located west of the town) (). Water has always been a big problem for the town, strongly hindering its expansion until 1956, date of creation of the drinking water system. Until then, the town had as a sole water source Orne champenoise (located a few hundred meters from the village), a pool (located at the end of the current impasse of the pond), often dry and seven springs, six of which were private or reserved for a certain population (clergy, municipal employees). These fountains still exist in the current street fountains and on the back of the church. Ecology ZNIEFF natural area An area of Saint-Georges-du-Bois is listed as "natural area of ecological interest, flora and fauna – Second Generation" number 004161 by Regional Directorate of the Environment. Described in 1999, the registration was validated in 2005. This area, with an area of 6 hectare, is part of the Gué Perroux woods located on the road to Souligné-Flacé (). The criteria for the regional management of the environment for the inclusion of this area are Bitter cress grows in very moist, shady places. This plant is edible and tastes like watercress. Sustainable development Like most French communes, Saint-Georges-du-Bois works towards a better environment and follows the recommendations of Grenelle Environnement. Thus, a proactive plan to reduce power consumption of streetlights is in progress; while gradually renewing the old lights and using low energy light bulbs or other renewable energy sources. The commissioning of a new wastewater treatment plant in 2009, after more than 2 years of work, has significantly reduced usage that is now well below current and future standards. Plans are to become more efficient with biological and