We made it to Las Clavellinas and its monstrous wall of Acropora Cervicornis, a reef-building coral that is a threatened species today but was clearly abundant in Caribbean reefs 7,000 years ago. Here we collected another five bulk samples (10-kilogram cloth bags), and ten smaller bags, that will be brought to Panama and painstakingly picked apart for their tiny shark dermal denticles (all 25 or so per bag), sponge spicules, mollusks, and corals. The amazing Mauro Lepore and Félix Rodríguez were the climbers-in-chief, but everyone on the team had the chance to hack a bag of samples out of the hard fossil wall.

A fossil staghorn reef