His root cellar smelled of nature decomposing life into new life, of mud coated rock, of saturated air. Caves smell like my grandfather. They smell of the earth. They smell of comfort. They also contain secrets of mother earth - valuable records of the past a natural genealogy.
Ancient pollen trapped in stone can reveal changes in vegetation.
Uranium-series dating provides a chronology. Water encased in calcite gives clues to the sources of primeval rainfall. Stable isotopes document changes between domination of C3 or C4 plants a handy trick to distinguish between past rain forests and savannas. These evidences combine to chronicle changes in ancient vegetation and climate above the cave. I need data for my dissertation.