Hatchet Bay Cave is located in northern Eleuthera Island, east-central Bahamas. It is the longest Bahamian cave known, with 2 kilometers of mapped passages. The cave is developed in bioclastic eolianite limestones of the Owls Hole Formation (Middle Pleistocene). The tilted limestone layers and tilted walls and ceilings of much of Hatchet Bay Cave are large-scale cross beds formed by a one-directional wind current in an aragonite sand dune environment.

Dissolution of the cave itself occurred during the Sangamonian Interglacial in the early Late Pleistocene (119 to 131 ka) (= Marine Isotope Stage 5e). The interval from 119,000 to 131,000 years ago was a time of globally higher sea level than at present. During that sea level highstand, a groundwater aquifer in this part of Eleuthera Island was perched atop a slanted terra rosa paleosol horizon. Along the margin of the aquifer, near the flanks of Eleuthera Island, fresh water mixed with seawater, resulting in high-aggressivity water chemistry. Limestone dissolution occurred and Hatchet Bay Cave formed. Caves on carbonate islands that form this way are called flank margin caves.

The main passage in this cave is called Eleuthera Expressway.

A colony of bats occurs near the entrance.

This cave is open access, which has resulted in significant spray-paint graffiti defacement near the main entrance.

Hatchet Bay Cave was a guano mine in the 1800s and 1900s - much of the phosphorus-rich material was shipped to the Carolinas.

Travertine speleothem observed here includes dripstone (stalactites, stalagmites, columns) and flowstone. The most speleothem-rich area of the cave is called Carlsbad Room. One of the columns in that room is a calcified tree trunk.

Several bellholes occur in the ceiling of Eleuthera Expressway.

The photos in this album were taken in June 2010 during a geology field trip as part of the 15th Symposium on the Geology of the Bahamas. Cave geologist John Mylroie (seen in a few of these photos) led the tour through Hatchet Bay Cave.

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