How Raised Bogs Form

One type of bog is called a raised bog. It is common in Ireland. Long ago, glaciers scraped out hollows in the land. Those hollows filled with water. They became small lakes.

On the edges of each lake, plants grew. As they died, they began to fill up the lake.

As the dead plants piled up, they created a spongy mat. Over time, this mat grew. It trapped water in the lake. Mosses grew on top. This is a raised bog.