Paleontology and geology
There are no surface rocks of Silurian age in Nebraska; however, drill cores reveal that Nebraska was above sea level in the early Silurian. In the middle Silurian, a shallow, warm sea invaded the state. No fossils are available from these rocks, but they would be similar to middle Silurian reef fossils in nearby states, and might included brachiopods, "chain corals," snails, and other marine invertebrates. In the late Silurian the sea withdrew again to leave an eroding land surface.