Igneous And Fossil

Vesicular basalt (weathered volcanic rock)

Basalt; chiefly plagioclase feldspar, pyroxene, and commonly olivine, with iron oxides

Weathered vesicular volcanic rock, likely basaltic scoria

Vesicular basalt/scoria; mainly plagioclase, pyroxene, and iron-rich glass or oxides

Weathered brown rock fragment, possibly iron-rich basalt or breccia

Tentatively basaltic rock; exact identification requires testing

Fossiliferous limestone, possibly coral-bearing

Calcitic limestone (mostly CaCO₃; fossil fragments may include ancient colonial coral or shell material)

Possible fossilized bone fragment

Indeterminate fossil bone; no species can be identified from this image

Fossilized bivalve shell fragment

Bivalvia; commonly aragonite or calcite (CaCO₃), often recrystallized during fossilization

Likely weathered quartz or feldspar grain

Uncertain; possibly quartz (SiO₂) or a feldspar mineral

Chalcedony (Agate)

Silicon Dioxide (SiO2)

Polished fossiliferous limestone

Bioclastic limestone, chiefly calcite (CaCO₃)

Fossilized coral or stromatoporoid fragment

Tabulate coral (e.g., Favosites) or stromatoporoid; exact identification requires microscopy

Weathered fossiliferous limestone

Calcitic limestone; predominantly calcium carbonate (CaCO₃), commonly containing fossil fragments

Crinoid Stem Fossils (Indian Beads / St. Cuthbert's Beads)

Crinoid columnal ossicles (phylum Echinodermata)

Likely quartz-rich stone or shell fragment

Uncertain; possibly quartz (SiO₂) or a calcareous shell fragment (CaCO₃)

Fossil in Shale

Fossiliferous Shale

Weathered chert or silicified limestone nodule

Microcrystalline quartz (SiO₂), possibly replacing limestone; exact identification requires testing

Fossiliferous limestone

Bioclastic limestone, primarily calcite (CaCO₃), containing marine shell or coral fossils

Vesicular basalt (likely scoria)

Basaltic volcanic rock; chiefly plagioclase feldspar, pyroxene, and iron-rich minerals, with vesicles from trapped gas

Orbicular/mafic river pebble with dark dendritic mineral patterns

Likely altered basalt or andesite; dark markings may be manganese-oxide dendrites (MnO₂-rich coatings)

Fossiliferous limestone concretion

Calcite-rich limestone (primarily CaCO₃), possibly containing a fossil shell or coral fragment

Polished fossiliferous limestone, possibly coral or shell fossil

Calcite-rich limestone (CaCO₃), with probable fossilized skeletal structures

Weathered limestone pebble

Limestone, predominantly calcite (CaCO₃), possibly fossiliferous or oolitic

Weathered fossiliferous sandstone or mudstone cobble

Lithified siliciclastic sediment; the raised curved feature may be a trace fossil or shell impression

Weathered limestone or calcareous sandstone

Calcite-rich carbonate rock, chiefly calcium carbonate (CaCO₃), possibly fossiliferous limestone

Fossiliferous Limestone or Shale

Biomicrite (if limestone) or Fossiliferous Shale

Fossil shark tooth

Likely fossilized shark tooth, possibly *Carcharocles* or *Otodus* species

Chalcedony (Common Opal variant)

Silicon dioxide (SiO2) with varying levels of hydration

Fossil shell fragment, likely brachiopod or bivalve

Indeterminate fossilized marine mollusk or brachiopod; mineralized calcite shell in a carbonate matrix

Weathered fossil shell fragment

Likely molluscan shell, composed mainly of calcium carbonate (aragonite or calcite); exact taxon is indeterminate from the image

Vesicular basalt (lava rock)

Basalt, a fine-grained mafic volcanic rock; chiefly plagioclase, pyroxene, and possibly olivine

Fossil shell or shell fragment

Likely a calcareous bivalve or gastropod fragment; precise identification requires locality and microscopy

Fossiliferous limestone (likely crinoidal or shell limestone)

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

Silicified oyster fossil

Fossil oyster shell, commonly Ostrea or Crassostrea, replaced or encrusted by chalcedony/quartz

Likely vertebra fossil or bone fragment

Indeterminate fossilized vertebra; mineralized hydroxyapatite, commonly Ca₅(PO₄)₃(OH)

Fossilized Crinoid Stem in Limestone

Crinoidea (Class) in Calcium Carbonate (CaCO3) matrix

Fossiliferous Limestone

Limestone with embedded fossil cross-section

Weathered fossiliferous limestone, likely coral or shell fragment

Calcite (CaCO₃), biogenic limestone; exact fossil taxon indeterminate from the image

Fossilized shell fragment, likely bivalve

Bivalvia indet.; commonly preserved as calcite (CaCO₃) shell material

Fossil shell fragment, likely bivalve or brachiopod

Indeterminate fossilized mollusk/brachiopod; commonly calcite (CaCO₃)

Weathered iron-rich rock, likely laterite or vesicular scoria

Probably iron-oxide-stained basaltic scoria; exact identification requires testing

Fossilized shell fragment

Indeterminate fossil mollusk; likely a silicified or mineral-replaced bivalve/gastropod fragment

Orbicular granite (likely weathered granitic rock with feldspar phenocryst)

Granite; chiefly quartz, K-feldspar, plagioclase, and biotite/hornblende

Orbicular granite (likely Rapakivi-type granite)

Granite, chiefly quartz, alkali feldspar, plagioclase, and biotite/hornblende