Part geology lesson, part tourist attraction, Harrison’s Cave is touted as one of the "Seven Wonders of Barbados." Carved by subterranean rivers coursing through the island’s limestone heart, the cave on view today has been considerably altered to accommodate an electric tram system that takes visitors through a mile-long section of the caverns. While the tram stops twice to allow passengers to disembark, the tour does feel a bit like a ride through an underground tunnel more than a potholing excursion. The guide’s polished spiel competes with the whine of the electrical engine, plus it’s difficult to get a close look at some of the formations while the tram is moving. Still, those who want a good overview of Barbados’ unique geology would do well to start here.
Geologically, Barbados differs from neighboring islands, which were formed by volcanic action. Barbados was born when the Caribbean tectonic plate was pushed up and over the Atlantic plate. During this process, the resulting volcanic eruptions gave birth to the surrounding islands, yet Barbados’ genesis lay in the ancient seabed and more recent coral beds being gradually lifted from the sea. Having visited St. Lucia several years back, it was immediately obvious to me that the gently rolling hills of Barbados were formed differently than the rugged terrain of St. Lucia, with its jagged pitons.
Six-sevenths of Barbados is covered by what was once coral reef – a porous coralline limestone easily penetrated by water. This is why there are few streams or rivers on the island -- water seeps straight through the limestone, creating Barbados’ famously pure, clean well water in the process. There’s little sedimentary run-off, too, which contributes to healthy coral reefs offshore.
As the tram wended its way through the cave, I noted that Harrison’s Cave was by far the drippiest I’d ever been in, with water percolating continuously from the surface. I was tempted to ask how the rate of stalactite and stalagmite formation compared with less watery caverns, but the opportunity never arose.
Those who have seen spectacular caverns such as Mammoth Cave in Kentucky would probably judge the more recent formations at Harrison’s Cave less impressive. But what Harrison’s Cave lacks in monstrous stalactites, stalagmites, and columns, it makes up for in hauntingly lit underground pools and silky displays of smooth, white flowstone. One memorable view was of a cascading waterfall plunging into a beautiful aqua lake with a roof of icy-white stalactites above – an enchanted spot. There’s little mineral coloring to the formations – no cuprous green or dusky ferrous tinges – since few mineral impurities exist in the limestone.
It’s best to visit the cave early, as the tram only accommodates a set number of passengers, causing something of a backup later in the day. A modern complex above ground features an excellent introductory film as well as the inevitable gift and snack shops, while the parking lot teems with vendors eager to benefit from the influx of tourists.