Or seen exposed layers of rock on a bare column in Arizona?
The rock there is interesting, and often very attractive.
All of this and much more was determined by studying and analyzing the rocks we can see along the walls of the Grand Canyon.
We can do this all over the world and make amazing discoveries about the history of our planet.
You can test out of the first two years of college and save thousands off your degree.
Anyone can earn credit-by-exam regardless of age or education level.
Many places that used to be sea beds are now on land and can easily be studied by humans. These include rocks from the Paleozoic and Proterozoic eras.
At the Grand Canyon a big part of the Paleozoic era can be seen, with a total of 11 individual layers---a mixture of sandstone, limestone and shale.
Underneath the Paleozoic rocks should be Proterozoic (or Precambrian) rocks from 542 million or more years ago, since the Proterozoic era preceded the Paleozoic time period.
Much of the Earth's geology consists of successional layers of different rock types, piled one on top of another.
The most common rocks observed in this form are sedimentary rocks (derived from what were formerly sediments), and extrusive igneous rocks (e.g., lavas, volcanic ash, and other formerly molten rocks extruded onto the Earth's surface).
This document is partly based on a prior posting composed in reply to Ted Holden.