(6) http://en.wikipedia.org/wiki/Image:James_Hutton.jpg. GNU-FDL.(7) http://commons.wikimedia.org/wiki/Image:Igneous_structures.jpg.
GNU-FDL.(8) http://en.wikipedia.org/wiki/Image:Elisabeth02.jpg. GNU-FDL.(9) http://commons.wikimedia.org/wiki/Image:
Helgoland_Lummenfelsen_22067.jpg. GNU-FDL.(10) http://en.wikipedia.org/wiki/Peridotite. GNU-FDL.
(11) http://commons.wikimedia.org/wiki/Image:Phlogopite_peridotite.jpg.
GNU-FDL.
(12) http://en.wikipedia.org/wiki/Sandstone. GNU-FDL.
(13) http://commons.wikimedia.org/wiki/Image:HN999sRamon~SRP-tours6.jpg.
GNU-FDL.
(14) http://en.wikipedia.org/wiki/File:Pahoeoe_fountain_edit2.jpg. Public
Domain.
(15) http://en.wikipedia.org/wiki/White_house. GNU-FDL.
(16) http://en.wikipedia.org/wiki/Image:DirkvdM_rocks.jpg. GNU-FDL.
(17) http://en.wikipedia.org/wiki/Image:Balanced_Rock.jpg. GNU-FDL.
(18) http://commons.wikimedia.org/wiki/Image:Teidepumice.jpg. GNU-FDL.
(19) http://en.wikipedia.org/wiki/Image:
Perpendicularly-fused_Metamorphosed_Sedimentary_Layers.jpg. GNU-FDL.
(20) http://en.wikipedia.org/wiki/Image:Rainbow_obsidian.jpg. GNU-FDL.
(21) http://commons.wikimedia.org/wiki/Image:
Berraco_%28Plaza_del_Castillo%2C_Ciudad_Rodrigo%29.jpg. GNU-FDL and
CC-BY-2.5.
(22) http://en.wikipedia.org/wiki/Image:Granite_Yosemite_P1160483.jpg.
GNU-FDL.
(23) http://en.wikipedia.org/wiki/Rhyolite. GNU-FDL.
(24) http://en.wikipedia.org/wiki/Track_ballast. GNU-FDL.
(25) Geoff Ruth, Dusy Basins.. CC-BY-SA.