1. 1Daily Warm-Up Exercises Day 47 What are index fossils? They are the remains or traces of organisms that lived for only a short time, but in many places around the world. Why are index fossils important to geologists? They can be used to compare the ages of rock layers. All rock layers that contain the same index fossil are about the same age.

2. 2 Differential Erosion (Part 4) Investigation 3 Grand Canyon Rocks

3. 3 Differential Erosion  Landforms shaped like steps or cliffs are formed by differential erosion.  This happens when a mountain or plateau is made out of both soft, weak rock and hard, strong rock.  The softer rock wears away faster, leaving behind knobs and cliffs of harder rock.

4. Monument Valley  Can you find Monument Valley on the Colorado Plateau map? (Pg. 32)  Page 19  This area is famous and has been used in many movies.  Show video Daily Warm-Up Exercises4

5. 5 Chuar Butte Observations  Turn to page 18 in the Resources book.  This is a picture of Chuar Butte.  Can you find this on your Grand Canyon map? (Pg. 3)  Use the picture to answer the questions on the Chuar Butte Observations sheet (page 17)

6. 6 Examples of Differential Erosion  Turn to pages 20-21 in the Resources book.  Choose three images that are good examples of differential erosion.  Sketch the landforms in 3 images on the back of page 17 and label it with the name of the national park you sketched.  Label which layers are harder/stronger and which are softer/weaker.  Label which layers are limestone, sandstone or shale.