Margaret B. Fuller Boos' primary interest was in mapping and interpreting the granite intrusives on the Colorado Front Range and discovered the first lithium pegmatite in the front range. During her time as a geology professor, she mapped the granite intrusives and pegmatites in the Denver Mountain Parks area. In 1922, Boos mapped the Precambrian area north and south of the Big Thompson River, as well as the extent of the Longs Peak and Mt. Olympus granites. In 1924, she continued her research in the Big Thompson River, yet this time focusing on the glacial features along the river. After her marriage to Charles Maynard Boos, the newly weds both went out to work for Empire Gas and Fuel as petroleum geologists.