While a practising physician, Gesner pursued his passion for geology. In 1836, he published a study on the mineralogy of Nova Scotia, which included a detailed geological map providing information on the key deposits of iron ore and coal in Nova Scotia. In 1838, he was appointed Provincial Geologist for New Brunswick with the mission to undertake a similar geological survey. In the course of this survey, in 1839, Gesner discovered the bituminous asphalt substance albertite, which he named after Albert County, New Brunswick where it was found.