History of the Earth

2. A vein of rock that cuts across a rock's layer is younger than the surrounding layers.
6. Fossils can be used to identify the relative age of the layers of a rock formation.
7. The method of putting events in order in which they happened.
8. A gap in the geological record that shows where rock layers have been lost due to erosion.
9. Sediments are originally deposited in horizontal layers.
13. Sedimentary layers extend sideways in all directions until they thin out or reach a barrier.
14. The era in which modern human live.

1. Any part of a previous rock layer, like a piece of stone, is older than the layer containing it.
3. In undisturbed rock layers, the oldest layer is at the bottom and the youngest layer is at the top.
4. A scientist that studies dinosaurs
5. The longest span of time at the beginning of Geologic time.
10. The largest divisions of time on the geologic time scale
11. The study of rock and rock formations.
12. Scientist suggest that our Earth is more than ____ billion years old.