He has been described as “a giant of natural history in early-day Colorado” who “cast an enormous intellectual umbra.”[2][3] Born in Marshalltown, Iowa, on April 30, 1865, Henderson was a ninth-generation American.

The collection at that time consisted of “a few fossils and mollusk shells, a small collection of rocks and minerals, and several mounted bird and mammals.”[1][4] “During his early years as judge and curator,” according to one source, “Henderson found time to earn a bachelor's degree from the university.

Instead of attending graduation, he went exploring for fossils.”[2] Working closely with Professors Theodore Dru Alison Cockerell and Francis Ramaley, he expanded the collection.

[2] In 1909, the Museum was declared a separate University department with a $500 annual budget, and Henderson was granted a salary and a full professorship.

His notebooks have been described as “paint[ing] a vivid picture of a changing Colorado, as horses-and-buggies give way to cars, cities grow, and wild landscapes retreat.

His complete checklist of freshwater and terrestrial mollusks of Idaho, published in 1924 (a supplement was issued in 1936), was not superseded until the year 2000.

“Read the early literature on Colorado birds,” wrote Kevin J. Cook, “and the name 'Junius Henderson' pops up again and again.