The Chesapeake Bay is famous for it's large, complete, and exposed Miocene Formation deposits, best know at the Calvert Cliffs, but extending from Fairhaven to St. Mary's. Since my daughter was small, we would walk these beaches, picking up shark teeth and molluscs and talking about what the Bay might have been like then. When she was very small, it was simple, fun talk of a time when the Bay was ocean, after dinosaurs but before people. Even a small child can see that shells belong to organism that are gone, and with a little explanation, to organisms that can't and don't live in brackish water.
Shark Toothed Dolphin (Squalodontidae)
Some of our favorite places are the cliffs and beaches near Fairhaven. While the beaches are not littered with the large scallop shells that characterize Calvert Cliffs beaches, there are many small sharks teeth and other small shells, and occasionally something more interesting. Once, to our delight, a small section of vertebrae had been exposed by the passage of a tropical storm.
They were all broken up and scattered, and it took some time to assembly and identify the remains, not being a paleontologist and having only a rudimentary knowledge of mammal skeletons. A trip to the Smithsonian in Washington made it clear that it was a marine mammal, and trip to the Smithsonian Naturalists Center made it clear that it was a dolphin or small whale. Some reading about the formation and the discovery of a small whale skull by others, a short time later only a few feet away, makes it likely that this is from a small whale about 14 million years old.
Arrowheads are always tricky to date, even more so when found loose on the surface. Since there are no context or excavation clues, the best that can be done is compare this artifact to others that are better dated. This could be anywhere between one thousand and several thousand years old; I'm guessing Bakers Creek style, about 2,400 BCE since we have found others of that type in the area, but it's worn and could be older, perhaps 5,000-7,000 BCE.
Note: Since nearly all of the cliffs and beaches adjoin private property, stay on the beach and be a quiet visitor. Please do not dig anywhere as erosion is a serious problem. Additionally, that many of these cliffs are not too stable, and that after heavy rains collapses and land slides are common. There have been fatalities and some cliff beaches are closed for this reason (the cliffs grow progressively less stable, heading south). Do not climb on the cliffs.