Withrow Moraine
What to look for: Go east from Waterville until you reach the town of Farmer. Then go north. Just outside of the town of Withrow, you’ll see the moraine in the picture. It’s called a terminal moraine because that’s where the glacier terminated (ended).

Interest facts:
A moraine is a ridge or low hill that is formed by a glacier when the ice melts. When a glacier moves and because it’s heavy, it causes rocks and dirt to be pushed. It’s like a giant bulldozer. Then the glacier melts and leaves behind piles of rock and dirt known as moraines.

Split Rocks – Weathering
What to look for: When you drive from Waterville to Withrow or Mansfield, you’ll see a lot of erratic rocks (left behind by glaciers). Some are split into two parts. Some aren’t. Why?

The erratic splits because of weathering. A special type of weathering happens when things freeze and thaw over and over. Water expands as it freezes. Water slips through small cracks in the rock and makes the cracks bigger each time there is a freeze. When you see these rocks, walk up close and really look at the split part.

Geologist = A specialist who studies the earth.

Geology = A science that deals with the history of the earth as recorded in rocks.

Northwest Origins - An Introduction to the Geologic History of Washington State