Julia Anna Gardner, geologist, was born on January 26, 1882, in Chamberlain, South Dakota, the only child of Charles Henry and Julia (Brackett) Gardner. She spent most of her childhood in South Dakota but completed high school in North Adams, Massachusetts. In 1907 she obtained a master's degree at Bryn Mawr University, where she had taken undergraduate training. She earned her Ph.D. in paleontology at Johns Hopkins University in 1911. Until 1915 she worked as an assistant in paleontology at the university and as part-time geologist with the Maryland Geological Survey. She was then employed by the United States Geological Survey in Washington, D.C.
Although Gardner's initial research concerned the Upper Cretaceous in Maryland, she devoted most of her career to studying the Tertiary beds in the Coastal Plain, including areas from Maryland south into Mexico. She began working in Texas in the early 1920s, often in consultation with petroleum company geologists. In addition to shorter papers, she prepared The Midway Group of Texas, a bulletin on stratigraphy, comparing the Midway with rocks of similar age in the United States and abroad. In it she described some seventy new species of Texas fossils for the first time. Research on Gulf Coast fauna took Gardner into Mexico during the 1930s and 1940s. In 1945 the Geological Society of America published her findings under the title Mollusca of the Tertiary Formations of Northeastern Mexico.
Gardner served as president of the Paleontological Society in 1952. In 1953 she became the third woman to hold the vice presidency of the Geological Society of America. Upon retirement from the United States Geological Survey, she received the Distinguished Service Medal, the Department of the Interior's highest honor. She died on November 15, 1960, in Bethesda, Maryland.