The rock layers of the Grand Canyon can be confusing, especially if you are not good at memorizing strange names.

There are a couple of mneumonics that can help for the rocks since the great unconformity. Note that they leave out the Surprise Canyon Formation, as it is found only in a few locations.

The kid-safe version: Know The Canyon's History - Study Rocks Made By Time.

The adult version: Kissing Takes Concentration However Sex Required More Breath and Time

Both of these classify the Supai as one rock, not four.

I don't know a good mnumonic for the oldest rocks - please let me know if you have one.

Here's a little illustration I wrote to explain show the rock layers.