Named in honor of Ursula B. Marvin {1922– }, geologist at the Harvard-Smithsonian Center for Astrophysics, well-known for her outstanding mineralogical and petrologic research on meteorites and lunar samples. Her meteorite studies have focused in recent years on the rich wealth of samples from Antarctica, and she was also involved in collecting them. This work also led to her analysis of dust grains, some of them of volcanic origin, in Antarctic ice samples. Her discovery of cordierite in an Apollo 15 lunar sample strongly suggested that this particular rock must have originated more than 40 km below the lunar surface. Marvin has also been responsible for mapping sections of Ganymede, maintains a strong interest in the history of meteorites and currently serves as secretary general of the International Commission on the History of Geological Sciences. (M 18458) _ _.