I've been having the same problem! I thought the area wasn't available yet! Have you figured out how to get to the piramid?
to get to the pyramid you must first unlock Sanu's fertility which requires that you head to the tower opposite of the pyramid and get to the end of that, you'll know your at the right place if the archeologist is there (note: you'll actually need to have talked to the archeologist in the neko town to get her to show up there.)