What are arches and how are they formed?

Weathering and erosion form arches over a long period of time

They are sometimes referred to as natural bridges.

• Natural arches, or natural bridges, start life as a narrow ridge between two hills or mountains. Over time, a portion of the interior of the ridge is weathered away, while the bulk of the ridge resists weathering, resulting in an arch or bridge.

Sandstone ArchA natural arch in Nevada

What caused it to fall?

Sometimes arches are caused by water. How do you think this arch was formed?

Mesas and Buttes

Where rock lie in horizontal layers, some harder than others, water erosion with wind and weathering over thousands of years can produces mesas and buttes. A mesa is a large, flat-topped island of rock that is left standing when the surrounding areas have been eroded away. When these erode or weather further, columns of rock called buttes remain jutting out of the landscape.

Examples of Buttes