ocr: Cleaving canyon walls at the rate of less than an inch a century, Deer Creek gnaws through Tapeats sandstone, deposited in the Cambrian period more than 500 million years ago. Vishnu schist, the oldest rock in the Grand Canyon geologic staircase, is nearly two billion years old. chunk of nearly ten million tons of cream- runners high, dry, and mad. Or low, wet, and colored concrete that looked out of placei in the mad, as was Bruce Babbitt, now the: secretary of red-rock sandstone of the middle of nowhere the interior but in 1987 a private citizen on a that is Page. Arizona. Few people were as ...
