Conglomerate with pebble-sized clasts and sandy matrix, Early Hesperian (corresp. to Early Archaean), Gale Crater, Mars

Isolated conglomerate boulder with dark matrix, ? Shawangunk Formation, Silurian, Pennsylvania

Graded conglomerate with boulder-sized clasts at base, Permian, Corsica, France

Compositionally and texturally very heterogenous conglomerate, Woodton Formation, Permian, New South Wales

Nagelfluh (molasse conglomerate of the North Alpine Foreland Basin), Miocene, S Germany

Cross bedded fine sandstone, Yellowknife Bay Formation, Early Hesperian (corresp. to Early Archaean), Gale Crater, Mars

Jacobsville Sandstone sample, Mesoproterozoic, Michigan

Variegated sandstone in artificial cave, Umm Ishrin Formation, Cambrian, Jordan

Cross-bedded, bitumen-stained sandstone, Lower Eday Sandstone, Middle Devonian, Orkneys, UK

Greywacke (matrix-rich, poorly sorted sandstone), Lower Carboniferous, Czech Republic

Fine sandstones associated with coal seam, Witten Formation, Upper Carboniferous, W Germany

Large sandstone slab with ripple marks on bedding plane, Schilfsandstein (Middle Keuper), Upper Triassic, SW Germany

Massive, cross-bedded dune beds, Forest Sandstone, Jurassic, Zimbabwe

Chunks of sandstone (stained by iron-bearing weathering solutions) in talus at Makthesh Katan, Lower Cretaceous, Negev, Israel

Microscopic image of glauconite-bearing sandstone (crossed niccols), Buchak series, Paleogene, Ukraine

Laminated argillite with microfossils (arrows) in thin section, Appekunny Argillite, Mesoproterozoic, Montana

Massive mudrock, with dropstone, Konnarock Formation, Neoproterozoic, Virginia

Kukersite (highly fossiliferous oil shale), Ordovician, Estonia

Sydney Mines Formation, Upper Carboniferous, Cape Breton Island, Nova Scotia

Slabs of whitish weathering shale with impressions of reptile skeletons, Whitehill Formation, Lower Permian, Namibia

Variegated mudrocks, with erosional features, Moenkopi Formation, Lower Triassic, Capitol Reef, Utah

Silty mudstone sample with neuropteran insect fossil, Yixiang Formation, Lower Cretaceous, Liaoning

Close-up of laminated oil shale, Messel Formation, Eocene, Germany

Loess (eolian silt) sample, Quaternary, NE France

Dolomitic mudstone, Nuccaleena Formation, Ediacaran, South Australia

Glacial erratic lime mudstone cobble with orthoceratid fossil, originally from the Ordovician of S Sweden

Ockerkalk (dark bioturbated lime mudstone; polished slab), Silurian, Germany

Oolithic limestone sample, Salem Limestone, Lower Carboniferous, Indiana

Coral limestone, Lower Carboniferous, Scotland

Crinoidal red limestone, Hirlatzkalk, Upper Triassic/Lower Jurassic, Austria

Ammonitico rosso (nodular red lime mudstone), Lower Jurassic, N Italy

Brecciated dolostone, Pleš Breccia, Lower Jurassic, Slovakia

Lime mudstone, Gerofit Formation, Upper Cretaceous, Negev, Israel

Soft lime mudstone (chalk), Upper Cretaceous, Denmark

Examples of fine-grained limestones from the Upper Creatceous of Spain and Germany in thin section

Coquina (cemented coarse shell debris), Anastasia Formation, Quaternary, Florida

limestone rocks, Grignetta (Alps)

Slightly folded rock gypsum, Castile Formation, Upper Permian, New Mexico

Rock anhydrite in thin section (crossed niccols) showing gypsification, Hauptanhydrit, Upper Permian, Germany

Core samples of rock salt, Nong Bok Formation, Upper Cretaceous, Laos

Small sample of carnallitic rock, Cardona Saline Formation, Eocene, NE Spain

Banded iron formation sample, Moories Group (Barberton Greenstone Belt), Mesoarchaean, South Africa

Sample of massive lydite (‘siliceous shale’), Silurian, Germany