#columnar lava

Rocks often fracture creating joints. A common type of joint found in the park is columnar jointing, when lava fractures into a series of columns as it cools into rock. There are many different types of joints, and they can extend for miles in complicated systems. The type of joint can provide clues as to how a rock formed, and can affect how it weathers or breaks down in the future. Have you seen columnar jointing or other joint examples in the park? ___________ NPS Photo of a rock feature with numerous joints along the Palisades Lake Trail. Description: A rocky cliff built of layers of rocks broken into rough columns. ~kl