Because climate is a global phenomenon, the various lithofacies and [[Fossil assemblage|biofacies]] that reflect climate in the time interval of interest must be correlated accurately. Climates may change abruptly, and biostratigraphy provides the only practical means to demonstrate the contemporaneity, or lack of it, of contrasting climates.
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Because climate is a global phenomenon, the various lithofacies and [[Fossil assemblage|biofacies]] that reflect climate in the time interval of interest must be correlated accurately. Climates may change abruptly, and [[Biostratigraphic correlation and age determination|biostratigraphy]] provides the only practical means to demonstrate the contemporaneity, or lack of it, of contrasting climates.