peak of the Buxa hills. Kalimpong town is one of the well-known towns of this area. The Darjeeling Himalayan Railway (simply known as "toy train") has been listed in UNESCO world heritage sites. Terai region The Teesta River divides the area into two parts: the Terai to the west and the Dooars (or Duars) to the east. The Dooars region can be further subdivided into the Siliguri (Western) Dooars, the Jalpaiguri (Middle) Dooars, and the Alipur (Eastern) Dooars. The Terai ("moist land") is a belt of marshy grasslands, savannas, and forests at the base of the Himalaya range stretching southwards about 38 km. Above the Terai belt lies the Bhabar, a forested belt of rock, gravel, and soil eroded from the Himalayas. The Terai zone is composed of alternate layers of clay and sand, with a high water table that creates many springs and wetlands. The Terai zone is inundated yearly by the monsoon-swollen rivers of the Himalayas. The Terai–Duar savanna and grasslands is an ecoregion that stretches across the middle of the Terai belt, consisting of tall grasslands, savannas, evergreen forests, and deciduous forests. The Terai and Dooars region politically constitute the plains of Darjeeling District, the whole of Jalpaiguri and Alipurduar district, and the upper region of Cooch Behar District in West Bengal. The slope of the land is gentle, from north to south. The general height of the land is 80–100 m. The entire region is made up of sand, gravel, and pebbles laid down by Himalayan rivers including the Teesta, Torsa, Raidak, Jaldhaka, Sankosh, and Mahananda. North Bengal plains The North Bengal plains start from the south of Terai region and continue up to the left bank of the Ganges. The southern parts of the district Jalpaiguri, North Dinajpur baring some extreme northern regions, South Dinajpur, Malda, Alipurduar and southern part of Cooch Behar districts constitute this geographical region. The narrow land mass in the North Dinajpur district is known as Mahananda Corridor. This corridor runs north to south joining Malda with the plains of Jalpaiguri, Alipurduar and Cooch Behar. The entire part of North and South Dinajpur is silt laden plain. The Mahananda River divides the district of Malda into two parts. The eastern part (known as Barind or Barendrabhumi) consists of undulating plains and tilas, and is made up of old alluvium and is part of the Ganges Delta. In contrast, the western part