close up of fossil assemblage in horizontal layers of limestone in sandstone

cryptocrystalline paleontological fossilization sedimentation lithification paleontology evolutionary macroscopic sedimentary environment weathering sediments creatures education evolution undefined millions geologic deposits patterns chemical physical process lithify geology designs animals weather science biology massive history bedrock shells marine botany change record coral sized years paleo stone chert flint ocean floor study clues hand dead time old sea scale crinoid