[2] Hicks studied medicine at Guy's Hospital in London; in 1862, he became a member of the Royal College of Surgeons, and was licensed by Worshipful Society of Apothecaries.

[1] In St Davids, Hicks met palæontologist John William Salter, and became enamored with the burgeoning field of study.

Hicks discovered a new Lingulella in the red, Cambrian-era rocks near his hometown, and wrote of it to the Geological Society of London.

When he began his psychiatric work in Hendon Grove, this allowed Hicks much more time to devote to the geologic deposits in Middlesex.

[1] Hicks coined the terms Pebidian and Dimetian to describe the Precambrian rocks around St Davids; both descriptors were still used by scientists as of the 2010s.