William Smith, 'the Father of English Geology', worked one of the quarries in the region and was living in Tucking Mill (on the southern edge of Combe Down) when he produced one of the first geological maps, adding further historic value to the mines.
It was when William Smith was surveyor and subsequently engineer to the Somersetshire Coal Canal Company that he appreciated for the first time the regularity of deposition beds, and in 1799 he determined an Order of Strata and Law of Superposition for the rocks of the Bath region. Smith named many of the geological formations in the area and prepared the first coloured geological map which included the outcrop strata within a five mile radius of the Guildhall in Bath.
Subsequently William Lonsdale in 1832 divided the Great Oolite into an Upper and Lower Ragstone with an intermediate oolitic freestone. However, it was not until the work of Green and Donovan in 1969 that the two separate freestone units of the Combe Down Oolite and the overlying Bath Oolite were recognised.