In 1993, a remnant of the earliest known bridge-like structure in London was discovered alongside Vauxhall Bridge, when shifting currents washed away a layer of silt which had covered it. Dating to between 1550 BC and 300 BC, it consists of two rows of wooden posts, which it is believed would originally have carried a deck of some kind. It is believed that it did not cross the whole river, but instead connected the south bank to an island, possibly used for burial of the dead. As no mention of this or similar structures in the area is made in Julius Caesar's account of crossing the Thames nor by any other Roman author, it is presumed that the structure had been dismantled or destroyed prior to Caesar's expedition to Britain in 55 BC. The posts are still visible at extreme low tides.