A 200 million year old reptilian fossil was discovered by Alaskan scientists along the shores of Tongass National Forest. It was the low tide that made the discovery possible as a rare marine creature called Thalattosaurs was submerged in water and rocks. The last Thalattosaurs to survive was after the Triassic period, roughly 200 million years ago.
http://sanfrancisco.ibtimes.com/articles/189311/20110729/full-dinosaur-skeleton-found-alaska-rare-fossils-photos.htm
http://sanfrancisco.ibtimes.com/articles/189311/20110729/full-dinosaur-skeleton-found-alaska-rare-fossils-photos.htm