Post-Invasion Liberty Formation (IMAGE) Geological Society of America Caption The invader “horn coral” Grewingkia exposed in the post-invasion Liberty Formation. Credit: Ian Forsythe. Credit Ian Forsythe Usage Restrictions Credit must be given to the creator. Only noncommercial uses of the work are permitted. License CC BY-NC Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.