I dunno exactly where the Grand Canyon is, but as a Limey who has never crossed the pond, i'm gonna stick my neck out and say that it's somewhere near Texas...maybe even in Texas, perhaps.

But here is a link to something a bit more definite.

http://www.ridgenet.net/~do_while/sage/v8i5n.htm

Sure, maybe californians will point and laugh at this nonsense, but it is worrying when a small pressure group can exert this kind of pressure on a national landmark and how it gets described and presented to tourists and presumably students who want to learn about their nation's heritage.