Up around Jamestown, New York, in the hills, the fossil shells are so thick they form the soil. I can't say if they were freshwater or saltwater, but they are small, fairly intact, and have a primitive look to them.
Tonight, it was nice to see someone exploring the geological history of his area. The more you learn, the more interesting the view outside your own home becomes.
Where I live in Minnesota, almost everything was scraped away by the glaciers from our most recent ice-age. However, there is one cut through a hill that has exposed the bedrock granite.
The age and chemical composition of that granite, was found to be a very close analog to the rocks found on the Moon.
When you follow the Mississippi river South of St. Paul, it spreads out into a large lake around the city of Redwing Minnesota. The depression which forms the lake has also been identified as an ancient meteor impact crater.