 In 1861, Josiah Whitney, chief of the California Geological Survey, was searching for a qualified paleontologist to assist with the survey.After much inquiry, Gabb was recommended as the best authority in American Cretaceous paleontology and in 1862 he was appointed paleontologist to the survey.William H. Brewer, who led the field work for Whitney, described Gabb as “young, grassy green, but decidedly smart and well posted in his department--he will develop well with the hard knocks of camp.”

For the next several years Gabb did extensive work throughout California and beyond.