Sedimentary (Fossiliferous)

Chert (flint) nodule

Microcrystalline quartz (SiO₂), commonly called chert or flint

Limestone (likely weathered or plaster-coated)

Calcite-rich carbonate rock; primarily CaCO₃

Sandstone (likely Siltstone or Mudstone)

Clastic sedimentary rock (primarily SiO2 with various oxides)

Limestone

Calcium Carbonate (CaCO3)

Limestone

Calcium Carbonate (CaCO3)

Limestone (Weathered)

Calcium Carbonate (CaCO3)

Porous limestone

Calcite-rich limestone (CaCO₃), possibly fossiliferous or chalky limestone

Fossiliferous Chert or Limestone

Sedimentary rock containing fossilized marine invertebrates (likely crinoid stems or bryozoans)

Fossiliferous Limestone with Rugose Coral

Calcite (CaCO3) matrix containing Rugosa (order of extinct solitary and colonial corals)

Fossiliferous limestone fragment

Calcite-rich limestone, predominantly CaCO₃

Fossiliferous Limestone with Crinoid Stem

Sedimentary Rock with Echinodermata fossil fragment

Weathered quartz-rich sandstone

Quartz arenite to feldspathic sandstone, primarily SiO₂ with minor feldspar, mica, and iron oxides

Fossilized Brachiopod

Phylum Brachiopoda (likely Order Spiriferida or Orthida)

Polished fossiliferous limestone

Micritic limestone, likely bioclastic/fossiliferous calcite (CaCO₃)

Fossiliferous shale or mudstone

Siliciclastic shale/mudstone, chiefly clay minerals and quartz with fossil fragments

Weathered limestone

Calcite-rich limestone (CaCO₃), possibly fossiliferous

Weathered limestone

Calcite-rich limestone (CaCO₃), possibly fossiliferous

Polished fossiliferous chert or silicified limestone pebble

Microcrystalline quartz (SiO₂), possibly with calcite and iron-oxide inclusions

Likely calcite-rich limestone

Calcite (CaCO₃), probably micritic or fossiliferous limestone

Fossiliferous limestone (likely crinoidal or shell limestone)

Calcite-rich limestone; predominantly CaCO₃, with visible fossil fragments

Weathered limestone

Micritic to fossiliferous limestone, chiefly calcite (CaCO₃)

Likely calcite-rich limestone

Calcite (CaCO₃), probably micritic or fossiliferous limestone

Crinoid and Coral Fossils in Limestone

Fossiliferous Limestone with Rugosa (order) and Crinoidea (class)

Fossilized Knightia Fish

Knightia eocaena (set in fossiliferous Micritic Limestone)

Weathered limestone fragment

Calcite-rich limestone, chiefly calcium carbonate (CaCO₃)

Weathered river cobble, likely quartzite or sandstone

Indeterminate; probable quartz-rich sandstone/quartzite

Calcite-rich limestone

Limestone, primarily calcite (CaCO₃), possibly fossiliferous or dolomitic

Brachiopod Fossil in Chert

Phylum Brachiopoda within Microcrystalline Quartz (SiO2)

Limestone

Calcareous Sedimentary Rock (CaCO3)

Weathered limestone fragments

Limestone, primarily calcite (CaCO₃)

Quartz-rich sandstone or chert fragment

Indeterminate siliciclastic rock; likely quartz arenite or weathered chert

Mixed sedimentary rock and mineral specimens

Predominantly limestone, chert, sandstone, and iron-oxide-bearing clasts; exact identification requires testing

Tumbled fossiliferous limestone

Calcite-rich limestone (CaCO₃), possibly containing fossil fragments

Polished fossiliferous limestone

Bioclastic limestone, chiefly calcite (CaCO₃), with fossil shell fragments

Fossiliferous limestone pebble

Calcite-rich limestone (CaCO₃), containing weathered shell or crinoid fragments

Weathered fossiliferous limestone

Limestone, primarily calcite (CaCO₃), possibly containing fossil fragments or stylolites

Tumbled fossiliferous limestone

Bioclastic limestone, likely crinoidal or shell-rich limestone (calcite, CaCO₃)

Polished fossiliferous limestone

Bioclastic limestone, commonly called fossil limestone or marble-like limestone

Polished fossiliferous limestone

Bioclastic limestone, chiefly calcite (CaCO₃)

Fossiliferous Limestone Pebble

Limestone with fossil inclusion

Fossiliferous limestone fragment

Bioclastic limestone, primarily calcite (CaCO₃)

Limestone with fossiliferous textures

Bioclastic Limestone (CaCO3)