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Geology.com: Rocks: Pictures of Sedimentary Rocks
Presents photographs of examples of clastic, chemical, and organic sedimentary rocks, with short descriptions underneath each rock image. Each rock name is also linked to its own dedicated page with a great deal of additional information...
Wikimedia
Wikipedia: Oil Shale
When converted to petroleum, oil shale is a valuable resource produced by many countries around the world, including the U.S. Wikipedia discusses the geology, history, economics, and environmental considerations of oil shale.
CK-12 Foundation
Ck 12: Earth Science: Fossil Fuel Reserves
[Free Registration/Login may be required to access all resource tools.] Describes reserves of traditional and alternative fossil fuels.
Wikimedia
Wikipedia: Shale
Originating as clay or mud, shale is a sedimentary rock formed by deposits of small particles by slow moving water. Wikipedia includes color images and discusses composition and deposition.