Paleoshoreline
A paleoshoreline is a shoreline which existed, in the geologic past; note "paleo" means "old" or "ancient"; see perched coastline, a fossil coastline currently above the present coastline. Due to tides, the ocean advances and recedes, commonly twice per day. But sea level can advance and recede quite slowly, and finding paleoshorelines is more tricky. A lake may have a paleoshoreline. Just of the coastline of North America, in the last 15,000 years sea level has varied from over below, to as high as above its present level. That entire time, humans have lived in North America. Paleoshorelines have  been inferred, on Mars; see Burgsvik Beds and Martian dichotomy. Importance. Paleoshorelines capture valuable records of environmental change and can tell us about modern shelf ecosystems. These structures can indicate distributions of seabed features that are habitat of marine life; they also may shed light on the location of coastal resources once used by humans, thus so are of archaeological significance. External links and references. Physical geography Bodies of water