This fascinating volcanic site was named after Bartholomew James Sullivan, the first lieutenant on HMS Beagle, the ship that brought Charles Darwin to the Galapagos. This unique landscape is composed of a pair of eroded scoria lava cones which were engulfed by a recent (in geological terms) pahoehoe lava flow and which is considered one of the finest in the world.
There are easy to spot tuff cones, miniature spatter cones, and the imprints of tree branches in the once molten rock all over the island. Though the lava flow is over 170 years old, it looks much more recent because of its isolation on the island, that has greatly helped to its preservation.
Pioneer plants such as Brachycereus cactus and the endemic herb Mollugo are starting to colonize the dark grey rocks and lava, preparing the way for other plant species.