Cartography Books

“1. Ceylon was believed by Marco Polo to have been one-third larger in the past than it had become by his day -- with extensive lands to the north of the present island said to have been 'submerged under the sea'. In the process its circumference was reduced in size from 3600 units of measurement to 2400 units of measurement, i.e. by one-third.
2. Maps were in use amongst mariners in the Indian Ocean when Marco Polo was there -- either mappamundi or mariners' charts depending on the translation -- which continued to show the one-third larger, antediluvian Ceylon.
On the first of the two points above -- the one-third reduction in the size of Sri Lanka by flooding -- we cannot deny, having studied the inundation history of south India and Sri Lanka in earlier chapters, that the tradition which Marco Polo here preserves and passes down to us is essentially correct when set within the time-frame of the end of the last Ice Age.
Since approximately 7700-6900 years ago, when the last remnants of its landbridge to south India were inundated, Glenn Milne's maps suggest that there have been no significant changes in Ceylon's size. Prior to 7700 years ago the picture is very different, and as we go back through 8900 years ago, 10,600 years ago, 12,400 years ago, and 13,500 years ago, we note a progressive enlargement of Sri Lanka, exclusively in the north around the landbridge to south India, resulting from the lowered sea-level of those epochs. At its greatest extent the enlargement is of the order of one-third.”
― Graham Hancock, Underworld: The Mysterious Origins of Civilization