The remains of what has been described as a huge lost city may force historians and archaeologists to radically reconsider their view of ancient human history. Marine scientists say archaeological remains discovered 36 metres (120 feet) underwater in the Gulf of Cambay off the western coast of India could be over 9,000 years old. The vast city - which is five miles long and two miles wide - is believed to predate the oldest known remains in the subcontinent by more than 5,000 years. Debris recovered from the site - including construction material, pottery, sections of walls, beads, sculpture and human bones and teeth has been carbon dated and found to be nearly 9,500 years old. The city is believed to be even older than the ancient Harappan civilisation, which dates back around 4,000 years. Author and film-maker Graham Hancock - who has written extensively on the uncovering of ancient civilisations [said,] Cities on this scale are not known in the archaeological record until roughly 4,500 years ago when the first big cities begin to appear in Mesopotamia. Nothing else on the scale of the underwater cities of Cambay is known. There's a huge chronological problem in this discovery. It means that the whole model of the origins of civilisation with which archaeologists have been working will have to be remade from scratch," he said.