Talk about brilliant educational aids. The yellow strip
is a timeline that represents the 1.7 billion years since the oldest rocks in
Grand Canyon formed, starting on the right. Ivo is holding the left end, which
is present day. The Colorado began cutting through
all the rock about 4 or 5 million years ago, which is a long time, but that
began a mere 2 or 3 inches from Ivo's hand!. All the rest
of the time the rocks were being formed.