Canal fossils give clue to formation of Americas

Scientists in Panama have unearthed hundreds of animal fossils dating back 20 million years, which could shed more light on how and when the American continent became connected.Geologists from the U.S. Smithsonian Institution, which has a permanent base in Panama, say engineers digging to widen the Panama Canal have uncovered more than 500 fossils including teeth and bones of rodents, horses, crocodiles and turtles that lived before a land bridge linked North and South America."With these discoveries we will be able to get more information about the process by which the continual land bridge was formed," Smithsonian geologist Camilo Montes told Reuters.Since February, the geologists accompanied engineers on excavations to expand the canal, having been invited by the government to make sure nothing of value was destroyed.Scientists believe the South American and Caribbean tectonic plates collided around 15 million years ago, causing volcanic activity that eventually formed a thin strip of land linking the Americas and separating the Pacific and Atlantic oceans.The bridge was probably fully formed, in a way that mammals could walk over it, some 3 million years ago.By comparing the Panama discoveries to fossil records from each continent, paleontologists hope to determine where individual species came from. Volcanic debris embedded in the same layer of rock as the fossils will help pinpoint the time when the animal was found on either side of the land bridge."We will be able to get a much more precise date for when the continents started to close together," said Montes.