Larry J. Kreitzer, «The Plutonium of Hierapolis and the Descent of Christ into the 'Lowermost Parts of the Earth' (Ephesians 4,9)», Vol. 79 (1998) 381-393
After a general discussion of the myth regarding Demeter, Persephone and Hades/Pluto, the author discusses, in the light of coins of the early Neronian period (54-59 AD), the likelihood that the Plutonium of Hierapolis is the geographical spot the author wants his readers to imagine when they read in the Letter to the Colossians that Christ entered the lowermost parts of the earth.
story of the abduction of Persephone in Eleusis may be somewhat uncertain, the subsequent journeys of Demeter in search of her lost daughter have long been associated with the town through the mystery cult based there 19.
However, there is another strand of the myths surrounding the cult of Demeter and Persephone which associates them with Sicily 20. Some ancient sources even state that Sicily was sacred to Demeter and Persephone, and that the island was given by Zeus to his brother Hades as a wedding present when Hades married Persephone 21. A number of ancient sources set Hades abduction of Persephone in Sicily, usually near the village of Henna in the centre of the island 22, although the spring of Cyane in the city of Syracuse on the coast is another site sometimes so mentioned 23. The site of a cave or an underground cavern is a frequent feature in the locating of such legends. Thus, Diodorus Siculus Library of History 5:3:3 associates the story of Hades abduction of Persephone with the village of Henna due to the fact that there is nearby a large cave which contained an underground entrance (sph/laion eu0me/geqej ei2xon xa/sma kata/geion).
In short, there were a number of places within the ancient world which claimed to be the actual site where Hades descended to the underworld with his plundered maiden Persephone. It appears that the only requirements needed to substantiate such a claim were a cave or some unusual opening into the earth and a desire to anchor