Well, hello there! Have you ever been to the beach? I'm sure you have! And you know how the waves come crashing in and out, right? Well, imagine that happening for a very, very long time.
Over thousands of years, those waves can actually change the shape of the land, making it higher or lower in some spots. In some places, the waves have made the land higher up than where the new waves can reach, so they don't crash there anymore. That's what we call a "raised beach."
It's kind of like a step-up from the normal beach, like if you were standing on a really tall platform looking down at the waves. And sometimes, we can find things on the raised beach that tell us what used to live there a long, long time ago. Isn't that neat?