Ken Wild knew that somewhere in Virgin Islands National Park's tangle of mango, lime, and tamarind trees, intertwined with various palm species and thick, cloaking pockets of Sansevieria, was an ancient carving in rock. An old roll of film confirmed as much.

But where?

The images, taken from the roll that had itself gotten overlooked for an unknown period of time -- in the park's archives, not within its lush tropical forests -- included some of the well-known Taino carvings in a rock above a pool of water along the Reef Bay Trail. But then there was the other curious image, one without any water in sight and with a different, vertical, orientation of rock palette.

Several times Mr. Wild, the park's archaeologist, had searched on his own for the missing petroglyph without success. Then in late January he recruited a group of volunteers from Friends of Virgin Islands National Park to help with the hunt and they all set off down the Reef Bay Trail for the Taino petroglyphs, which would serve as the starting point....