S E D I M E N T A R Y R O C K S

Angular gravel, poor sorted, grains < 2mm

Detrital

S E D I M E N T A R Y

Rounded gravel, poor sorted, grains < 2mm

Conglomerate

Quartz Sandstone

Mostly quartz

Sand grain size

Arkose

Mostly feldspar Mostly Rock Fragments

Lithic Sandstone

Sand & Mud

Mud

Plant fragments Biochemical

R O C K S

Breccia

Mostly Silt, may contain fossils

Breaks into layers or blocks

Siltstone

Mostly Clay, may contain fossils

Splits easy into layers

Shale

Crumbles into blocks

Claystone

Easy to break, visible plant fragments, Brown, porous

Peat

Dull, dark brown, brittle; fossil plant fragments

Lignite

Black, layered, brittle, sooty Gravel sized shell/coral fragments

Shell/Coral fragments

Adapted From Richard M. Busch Editor; AGI/NAGT Laboratory Manual in Physical Geology

Garywacke

Sand sized shell/coral fragments Silty grains of microfossils Dark, fine grained, conchoidal fracture

Bituminous Coal Coquina

Fossiliferous Limestone Chalk Micrite