Most of the mountains here are made up of Shale/mudstone and other deposits from the Eocene Era. The deposits are know as the Green River Formation.
During that period This area was covered by a large inland lake. Water flowed from norther Arizona, Colorado, Wyoming, and from all over Utah into this large lake. The deposits are in layer after layers. These layers are typically Darker during the summer months, and lighter during the winter, and very thin. The average thickness that represents a year is .006 of an inch. Though some layers can be as thick as .350" thick or as thin as .0006 of an inch.
These are well known for holding fossils the fish from these layers are pretty well known. After a lot of searching i found some plant fragments, but nothing that impressive.
Well here at this location I noticed a Nonconformity in the geology. What is a nonconformity? Well actually there are a few types. But to explain simply, it is rock that has shifted and/or eroded then new deposits are laid on top of it. Because these deposits are always laid down flat you can see if there has been any change in the surface of the lake floor. Sometimes it is a little, sometimes a lot.
Here are the few types.
A - Is called an Angular Unconformity The ground has faulted, bent or twisted. Now new layers are being placed on top of it.
B - Is called a Nonconformity , The sedimentary rock is laid over the top of igneous or metamorphic rock. That rock has eroded or weathered and is now being covered over by the newer layers of sediment.
C - Is a Disconformity, This is where eroded materials are now having new material placed on top of it.
If you look at the rocks to the Southwest you can see how the materials do not line up.
Logging Tasks
Looking at the reddish stone layer and the layers above it:
1-Does they appear to be angled in a way that they are a Angular Unconformity? or a Disconformity? Why?
You can see where the larger blocks above those angle upward (look toward where the slide is taking place on the north end - It is more obvious)
2-Do these appear to be the same type or different?
3-What would these tell you about the lake, and the lake bottom at the time?
4-Looking above and below those layers to you see any others? 5-Look closer at some of the stones, what color is the stone you are looking at, can you see the layering? Do the layers flake easily or is it difficult?
Graphic from The Earth Through Time, Eighth Edition by Harold L. Levin
