Santiago Island

Santiago Island is the fourth largest island in the archipelago (585 km2)-has a fascinating geological history. It offers some good wildlife watching opportunities, but its most remarkable feature is terrestrial composition, which provides visitors interested in geology, volcanology, or succession with the opportunity to see age-old processes in current time.

The most popular visitor site is Puerto Egas, on the west side of Santiago , whose varied terrain provides rest and play places for humans and animals alike. The island's black sandy beach serves as a perfect spot from which to snorkel or to start a rousing game of soccer. Lava formations along the coast that have been eroded to form pools, caves, and inlets make the perfect habitat for interesting inter-tidal organisms like scuttling Sally Lightfoot crabs, algae-munching marine iguanas, and cuddling fur seals. A main attraction for geology buffs (not people with small bladders) is Darwin 's toilet, a rock formation that causes a vertical chute of water to rise when the waves collide with the rock face.

On the other side of Santiago , across the bay from Bartholome, is Sullivan Bay . Here, a century-old volcanic eruption has left a visible path of lava flow and an utterly barren landscape. Since the island is devoid of vegetation, with the exception of the occasional pioneering Brachycereus cactus or Mollugo carpetweed, the most distinctive features of this visitor site are the various igneous rock structures and lava types-pahoehoe (braided), aa (jagged), and schrict (ropy).