Below is a picture of the same type of formation as the first one above. This one, however, better shows the strata divisions near the bottom when conditions changed frequently enough (in geological terms) to leave their mark in the rock that eventually formed from the sediment. In contrast, the massive rock above this level shows only the slightest traces of strata and must represent a very long period of great stability of deposition in the environment. In a sense, we are seeing a long calm after a period of rapid change.
This was followed by another period of change (like war seems to follow peace, or a storm follows the calm). Only a bit of this younger rock is visible here near the top, but we can see more of it near the top of the first photograph on this page.
