Maw of Snails

From the introduction: North of the dry hills, East of the Pyre Sea, ancient diggings wound the earth. The Maw of Snails, a black shaft that births gastropod horrors each night to burn and wither in the unforgiving sun. Venerated as a portal to the underworld by the shepherd folk, scholars proclaim it a magical sink, a polluted arcane cyst, hoarding the lost treasures of history.