Brian Roemmele
@BrianRoemmele
we can only see what we think is possible...
参加 January 2010
44.2K フォロー中 489.4K ファン
The dark, layered Vishnu Schist at the bottom of the Grand Canyon formed approximately 1.7 billion years ago, exposed today only because the younger rock layers above it were eroded away.
もっと見る
