Ujjain is located in the west-central part of India, and is north of the upper limit of the Vindhya mountain ranges. Located on the Malwa plateau, it is higher than the north Indian plains and the land rises towards the Vindhya Range to the south. Ujjain's coordinate are 23°10′N75°46′E / 23.167°N 75.767°E / 23.167; 75.767 with average elevation of 494m metres (1620 ft). Region is an extension of the Deccan Traps, formed between 60 and 68 million years ago at the end of the Cretaceousperiod. In this region the main classes of soil are black, brown and bhatori (stony) soil. The volcanic, clay-like soil of the region owes its black colour to the high iron content of the basalt from which it formed. The soil requires less irrigation because of its high capacity for moisture retention. City is on the bank of river Shipra which falls into nearby flowing Chambal.