Stratigraphy is a geologic term defined as "The science of rock strata." Basically, it means looking at how sediments are deposited and interpreting the conditions under which these rocks formed. In the case of the pond at this site in Chemung County, New York, these sediments are still sediments, and have not yet been transformed into rock. Simply put, by looking at the changes in the sediments over time in the bottom of the pond, many questions about the changes that took place to the pond over time can be answered, such as "Did the water depth change over time?", "How high was the water table?" or "When did the lake change into a swamp, and why?"