How old is the Grand Canyon? - Creeks, Streams & Rivers
How old is the Grand Canyon?
How old is the Grand Canyon?,
By Becky Oskin, LiveScience's OurAmazingPlanet,
Jan 27, 2014,
Mother Nature Network,
Picture of Grand Canyon and all-text article.
http://www.mnn.com/earth-matters/wilderness-resources/stories/how-old-is-the-grand-canyon