Google Ocean features a layer in its program called the "Marie Tharp Historical Map." Although this view of the ocean floor is hardly crisp, it is still an important tribute to a remarkable geologist and cartographer who battled gender discrimination and academic infighting to turn the scientific world on its head in 1952 with the discovery of the Mid-Atlantic Ridge. The ridge is a "forty-thousand-mile-long underwater structure, quite possibly the largest geologic feature on Earth." Tharp, who died in 2006, would devote her life to drawing what had previously been hidden beneath the world's oceans; she struggled for recognition and funding almost until the day she died.

With her father's blessing, a young Tharp had the freedom to roam both physically and intellectually, but that all changed when she left home for graduate school and was "treated like a child" because of her gender. She landed a job at Columbia University's Lamont Geological Observatory, where the men boarded research ships and conducted field work and Tharp was "allowed to do only the jobs that require minimal brainpower."

In "Soundings," author Hali Felt follows the traces of Tharp's life by deftly balancing scientific explanations with the poetic. (An absolutely brilliant 2 1/2-page history of the Earth, broken down in a 365-day calendar, is a must-read.) Felt takes some literary leaps re-creating scenes and dialogue. She even tells the reader what it is like to track the life of someone she has never met. "If I could dream of her, I would. I'd dream of waking up, and of her being there in a chair waiting for me like some Ghost of Christmas Past." There is a personal, Didion-like voice in Felt's narrative approach that is not unpleasant to read. Thank goodness she knows that a little bit of this goes a long way.

Tharp's discovery was shared by the ambitious Bruce Heezen, who was her scientific collaborator and the great love of her life. Heezen, who died suddenly in a submarine in 1977 while exploring the Mid-Atlantic Ridge, went on all those expeditions that Tharp was prevented from joining. They never married, but together they created the "World Ocean Floor Panorama, a map of the Earth that would show, all at once and for the first time, the 70 percent of its surface that was hidden by water." The colorful fold-out map would be featured in copies of National Geographic.

After Heezen's death, the momentum of Tharp's life stalled. The grants and funding dried up and although she received two major awards from the Library of Congress in 1997 at an event attended by President Bill Clinton, she had no one to share them with. When she finally saw her work prominently displayed there, next to the journals of Lewis and Clark, George Washington's maps and the Emancipation Proclamation, she began to cry. "I wish that Papa and Bruce could see it," she said.

Stephen J. Lyons' latest book is "The 1,000-Year Flood: Destruction, Loss, Rescue, and Redemption Along the Mississippi River." He is at work on a book about the Driftless Area of the Upper Midwest.