What is Sedimentary Rock?

Sediment, usually in the form of clay, is deposited in layers on the bottom of all bodies of water, including rivers, streams, lakes and oceans. When a layer of sediment has been covered over by many other layers, the weight from those other layers creates tremendous pressure which presses the particles of sediment in the underlying layer together to form rock. Examples of sedimentary rocks include shale, limestone and sandstone.