2. What is rock strata? Strata- plural form of stratum
Stratum-  a layer or a series of layers of rock in the ground.

3. Determining Geological Ages
Relative Age Dating – placing rocks and geologic events in their proper sequence
Absolute Age Dating – define the actual age of a particular geologic event

6. What is cross-cutting?

7. Sometimes magma pushes, or intrudes, into cracks in existing rocks
Sometimes magma pushes, or intrudes, into cracks in existing rocks. When the melted rock cools and solidifies, the resulting feature is called an igneous intrusion.  The principle of cross-cutting relationships states that an igneous intrusion is always younger than the rock it cuts across.

8. How Impression Fossils Form
Cast forms when mold
is filled in with mineral
water
1. Shells
settle on
ocean
floor
Rock broken
to reveal
fossil cast
Rock broken
to reveal external mold
of shell
2. Shells
buried in
sediment
3. Mold, or cavity,
forms when original
shell material
is dissolved

9. Metamorphic Rock- formed when rocks are changed by heat and pressure
  Types of Rocks
Sedimentary Rock- formed when sediments are pressed & cemented together
Metamorphic Rock- formed when rocks are changed by heat and pressure
Igneous Rock- formed from melted rock that has cooled and solidified. 

10. Weathering and Erosion
Erosion- when rock fragments are moved by some force of nature Weathering- when rocks are broken down into smaller fragments Deposition - when rock fragments are laid down in a new location