Provide your best answer for the following question. Give ONLY the answer, no other words or explanation.
For example:

Answer: <most likely answer, as short as possible; not a complete sentence, just the answer!>.

The question is: A student is visiting a local limestone quarry and finds fossils of seashells. The quarry is located hundreds of miles from the ocean. The fossils best indicate that
this area was once below sea level.
The area was covered by a sea millions of years ago.