The earth displays a wide varaiaty of rocks, minerals, and fossils. Here are a few samples:

ROCKS & MINERALS:

FOSSILS:

If you want to be a fossil hunter, here are the major animal and plant groups, with a description of the fossil and the date of the rocks.

Name	Description	When Living
Invertabrates
Foraminifera	Small, multi-chambered. Large numbers.	Cambrian - Recent
Worms	Burrows, Tracks, tubes. Usually spiral.	Cambrian - Recent
Sponges	Thick-walled. Featureless or coarse.	Cambrian - Recent
Bryzoans	Thin-walled. Delicate pore network.	Ordovician - Recent
Graptolites	Springs, blades, meshwork. Have "teeth."	Ordovician - Carboniferous
Corals	Horns, tubes, or trees. Variable chains.	Ordovician - Recent
Anthropods	Segmented bodies, exoskeleton.
Trilobites	Flattened, often segmented.	Cambrian - Permian
Chelicerates	Fused. Confused with trilobites or insects. Rare as fossils.	Cambrian - Recent
Crustacea	Ornate carpace, or limbs.	Cambrian - Recent
Insects	Head, thorax, abdomen. Sometimes legs or wings.	Devonian - Recent
Brachiopods	Shells have symmetrical valves.	Cambrian - Recent
Mollusks	Very diverse group. Nearly all have calcium carbonate shells. Classified by shell structure.
Bivalves	2 valves, asymmetrical	Cambrian - Recent
Chitons	Ridged, tile - like plates.	Cambrian - Recent
Scaphopods	Curved, tapering.	Ordovician - Recent
Gastropods	Single asymmetrical spiral	Cambrian - Recent
Nautiloids	Single, taperimg straight or curving shell.	Cambrian - Recent
Ammonoids	Similar to nautiloids, but with a ventrical siphuncle.	Devonian - Cretaceous
Belemnites/ Squids	Crystalline guard encloses a tapering phragmocone.	Jurassic - Recent
Echinoderms	Most have five ray-symetry. Possess a complex nework of multifunctional tubfeet. All are resticted to marine environments.
Crinoids	Hanve head, arms and stem. Usually only stem is found	Cambrian - Recent
Asteroids	Its five sides are edged with solid calcitic blocks.	Ordovician - Recent
Echinoids	Sell of thin plates. Subspherical, 5-rayed symmetry or bilateral symmetry. Spines.	Ordovician - Recent
Blastoids	Usually found intact.	Ordovician - Permian
Ophiuroids	Have five snakelike arms.	Ordovician - Recent
Cystoids	Calyx of many small irregular plates. Have short stem.	Cambrian - Permian
Carpoids	Short stem, no arms.	Cambrian - Devonian
Vertebrates
Fish	Segmented musculature, brain, spinal cord, notochord, mouth, hollow gut, and gills.
Agnathans	Jawless, covered with fine scales.	Late Cambrian - Late Devonian
Placoderms	Heavily armored with large pectoral fins and other armor.	Early Cambrian - Late Carboniferous
Chondrichthiyans	Teeth, tooth plates, placoid scales, fin spines and calcified vertebra are fiybd,	Late Silurian - Recent
Acanthodians	Found as isolated parts	Late Silurian - Early Permian
Osteichthyans	Found as teeth, bones, scales, fin spines, and otoliths.	Late Silurian - Recent
Amphibians	Bones are solid or hollow, skull is composed of fused bony plaes, simple teeth.	Late Devonian- Recent
Reptiles
Anapsids	Solid bones, skull have no secondary openings.	Early Carboniferous - Recent
Diapsids	Limb bones are usually hollow. Teeth are held in with a single long root.	Late Carboniferous - Recent
Diapsids (Dinosaurs)	Bones have either thick walls and are hollow, or soldid. Skull is lightly buuilt.	Late Triassic - Cretaceous
Synapsids	Bones are soldid. Skull is often huge.	Late Carboniferous - Jurassic
Euryapsids	Pterosaurs have hollow bones. Some found in ocean sediments.	Triassic - Cretaceous
Birds	Skull is light, no teth. Vertebrae are saddle shaped with neural canal.	Late Jurassic - Recent
Mammals	Enamel-covered teeth, skull may bear horns or antlers. Human specimens may be found with tools.	Late Triassic - Recent
Plants
Algae	Preserved as microscpic single-celled plants.	Precambrian - Recent
Early Land Plants and Hepatophytes	Small, upright, leafless, branhing, shoots. No roots.	Late Silurian - Recent
Sphnopsids	Main stem with meny leafed stems brancing from it.	Early Devonian - Recent
Ferns, Lycopods, and Pteridosperms	Often spirally arranged stems and spors are present.	Silurian - Recent
Bennettites and Cycads	Flowers, needle-like leaves, and woody stems are present.	Triassic - Recent
Conifers	Seeds in cones, woody trunks and needle like leaves.	Late Carboniferous - Recent
Angiosperms	Preserved as wood, leaves, and sometimes flowes. Large leaves.	Cretaceous - Recent