1.  Clastic sedimentary rocks

Composed of rock and mineral fragments

ROCK TYPE

FORMED FROM

Claystone

Clay

Shale

Clay

Siltstone

Silt

Mudstone

Silt and clay

Sandstone

Sand

Conglomerate

Cobbles, sand, silt, and clay

2.  Organic sedimentary rocks

Composed of the remains of organisms

ROCK TYPE

FORMED FROM

Fossiliferous limestone

Shell fragments from coral reefs

Chalk

Shell fragments of marine phytoplankton

Bituminous coal

Peat

3.  Chemical sedimentary rocks

Composed of precipitated and evaporated mineral deposits

ROCK TYPE

FORMED FROM

Rock salt (halite)

Evaporated water

Gypsum

Evaporated seawater

Limestone and tufa

Precipitated calcium carbonate