The surface of the Earth is divided between the continents and the ocean basins. Continental crust is lighter than oceanic crust and, on average, continents are about 2.8 miles (4.5 kilometers higher than ocean basins). Visit http://earthfacts.com/ to learn more facts about the earth and you may also like our Facebook Page - https://www.facebook.com/Earthfacts.com. Marcia Malory is a Freelance Science writer, living in York, England.