Since no one found the footprints our captain decided to stop by the island on the next day to give us another chance and this time I found a picture of the island with the "X" marks the spot. I was able to find the area where the dinosaur footprints were. We figured out that unless you were there in the morning before the tide comes in you can't see them because they are under water and that's one of the reasons why no one found them the day before.
We were told that the dinosaurs stepped in clay, or something like it, and it hardened shortly after which created the footprints. The footprint was filled with sand and then covered with more rock which helped preserve it. With time the top layer of rock broke off and the sand washed out leaving the footprints for us to find.
This information about the process is only as accurate as I remember hearing it so please don't quote this on any kind of important paper you may be writing.