This rock is igneous and made of volcanic glass ocuring in different colors but often is black.
What is Obsidian
100
A V shaped valley eroded by a river.
What is a Canyon?
100
The super continent that was formed during the Earths making.
What is Pangea III III?
200
Composed of grains ranging in size from 0.02 to 2 mm in diameter. The grains are usually quartz.
What is Sandstone?
200
A fan-shaped deposit at the mouth of a river.
What is a Delta?
200
This era was the first era.
What is the Precambrian Era?
300
May be composed of the remains of sea creatures or from minerals precipitated from water. Calcium carbonate is the main ingredient. Fizzes when acid is dropped on it.
What is Limestone?
300
Nearly level area that has been eroded or where material has been deposited.
What is a Plain?
300
This era came after the Precambrian Era.
What is the Paleozoic Era?
400
The metamorphic form of limestone. Composed of crystalline calcium carbonate and other minerals. Crystals are obvious and connected. Color mat be white, green, pink, or other. Reacts to acid test.
What is Marble?
400
A mound, hill, or ridge of windblown sand.
What is a Dune?
400
We are currently in this era.
What is the Cenozoic Era?
500
This is igneous and is composed of cemented volcanic ash and glass particles. Could be considered as a sedimentary rock. Often light-colored and not very dense.
What is Tuff
500
A curve or loop in a river.
What is a Meander?
500
This period was when the Mississippi River was formed.