- Most of the rocks we find in Central New York are grayish rocks made
of sediment (sand, lime, and mud) laid down at the bottom of a shallow
sea a long time ago.
- We also find colorful rocks with crystals.
- Colorful crystal rocks are very common in the Adirondack mountains
in northeastern New York and in southern Canada.
- During the Ice Age glaciers scraped southward from Canada, and, like
bulldozers, they pushed colorful crystal pebbles and boulders along
in front of them.
- When glaciers melted they left these colorful pebbles behind.
- These pebbles are called "glacial erratics", and they are unlike most
of the rocks found in this area.
- Take a walk and collect several small rocks from around the school.
- Sort the rocks into three categories:
- Gray rocks - these are rocks made of sediment. Some might even
- Colorful crystal rocks - these are rocks that may have been carried
to your neighborhood by a glacier 12,000 years ago.
- Mystery rocks - these may be pieces of concrete or rocks carried
into your neighborhood by people.
How many colorful rocks did you find?
How many gray rocks did you find?
Did you find any rocks with fossils in them?
Did you find any mystery rocks?
Main Message: Classifying rocks can answer questions about the history
of an area.
Connections: Activity 7, "Ice Age Mud," will
allow students to classify rocks and fossils from the sediment surrounding