Chryssi can be considered a haven for marine fossil enthusiasts. One of the most impressive geological sights of the island can be seen east of the central beach, where you will find thousands of fossilized shells, mainly bivalves. Fossils form what is called a thanatocoenosis, which is to say dead shells that were gathered there perhaps by currents and over time fossilized.

Similar sites with fossils are found in other parts of the island, like Kataprosopo Beach, Avlaki, or Agios Nikolaos. A total of 49 species of organisms was identified by the researchers.