James Hall, once director of the Museum of Natural History in Albany, New York, recognized this and produced the first, extensively rich, description of the ancient inhabitants of what is now the northeast area of the United States. His publication, The Palaeontology of New York (1847–94) became the standard reference document.
At the time of these fossil depositions some 380 million years ago, the land mass around Cortland, New York, was located just south of the equator. As true of todays tropical waters, it abounded with life of numerous, diverse, species. The sea shallowly covered the land, encouraging organisms that thrived in warm, light-filled habitats. At this same time, higher organisms had begun to evolve body parts that allowed them to live partly on land. Advanced, vascular, plants like ferns began to dominate the land. In time, this entire area, complete with inhabitants, would become intombed under hundreds of feet of mud.
Aeons of time would pass. The land mass would drift northwards. The shells of some sea creatures would leach their calcium to the water to form limestone. Other minerals would form shales and sandstone. In the process, some of the inhabitants would leave impressions in the rock to reveal their identity.
Did you know? There has never been a single dinosaur fossil found anywhere in New York State. Although the giant reptiles certainly lived in the area, the only evidence found are tracks in the extreme southeastern part of the state. The geological processes which have occurred here in the last 65 million years seem to have eradicated any dinosaur remains.