'The first step is to establish what these so-called "floating islands" would look like. The image that comes up most frequently in the literature is a section of land, or at the very least a large mass of vegetation, being dragged out to sea during violent storms at river mouths.
Such events have been documented, albeit rarely. Tantalisingly, there have even been reports of vegetation mats carried by the South Equatorial Current between the Niger and Congo Rivers of Africa and the coast of Brazil – exactly the kind of occurrence required for our monkey odyssey.
40 million years ago, the Atlantic Ocean could have been crossed on a raft in 14.7 days
If these hypothetical rafts had vertically standing trees on them – as historical rafts reportedly have had – Russell Ciochon, now at the University of Iowa, and Brunetto Chiarelli from the University of Florence suggest that it would even have been possible for them to act as sails.
Research into the ancient flow of currents (examining geological features such as sedimentary structures) indicates that strong currents in a westerly direction from West Africa did indeed exist in the late Eocene, as they do today. Nevertheless, crude estimates made by palaeontologist Elwyn L Simonsindicated that relying on currents alone, the transatlantic journey would take a minimum of 60 days – probably longer than even the toughest of monkeys could last."