Background
Gidley was born in 1866, in Springwater, Iowa.
Gidley was born in 1866, in Springwater, Iowa.
He attended Princeton University in Princeton, New Jersey, and received a Bachelor of Science degree in 1898 and a Master of Science degree in 1901. He later attended George Washington University, and earned a Doctor of Philosophy in 1922.
He began collecting fossils during childhood. He died in 1931. He remained at this job until 1905, after which he joined the United States National Museum as the Preparator in the Section of Vertebrate Fossils. Four years later, in 1912, he became an Assistant Curator at USNM, a position he held until his death.
Gidley studied various fossil mammals throughout his career, including prehistoric rodents and horses.
He described the species Equus scotti from Texas in 1899, and the three-toed horse genus Neohipparion from Nebraska in 1902. He began seeking remains of Pleistocene humans in Florida in the 1920s.