Her research career, supported in large part by the U.S. National Science Foundation and the Whitehall Foundation, included a number of outstanding discoveries. Her work on the early evolution of land plants showed that higher land plants first appeared in the Middle Ordovician 40 million years earlier than had been previously thought. This discovery, which faced great opposition, is widely accepted today and used in many textbooks. Her masterful book-length monograph on nonmarine paleocology is widely used as a synthesis of what was known in this area up through 1988.
At the time of her death, she was investigating the nature of atmospheric carbon dioxide present since the Cambrian. Her compilation and correlation of a massive amount of botanical and geologic data which will substantively revise previous estimates. This work will be completed by her colleagues. She was also working on a groundbreaking account of the evidence for a widespread Precambrian nonmarine biota, chiefly at the bacterial level.
She taught and mentored many students who found her work and ideas highly original. Her enthusiasm encouraged many to forge ahead in their respective areas. Her death deprives the scientific community of a highly original, innovative worker who undoubtedly would have provided even more significant contributions had time permitted. She will be sorely missed by many colleagues, students, and friends.
Dr. Gray was devoted to animal rights and welfare. Memorial contributions may be made to Greenhill Humane Society. There will be no memorial service at her request.