I hunt fossils on an all-too-infrequent basis. Mainly marine fossils like shark teeth. I-95 is a great example to show folks the shoreline for where the sea used to come up to. East of I-95, lots of marine fossils/shark teeth. West of I-95, very little to none until you get towards the Mississippi. Holds pretty true until you get down to Florida which was pretty much under water 5-50 MM years ago.

Another geological fact with the dividing line, some of the richest titanium deposits run down the i-95 corridor as it was deposited along the shorelines of those ancient seas. Dinwiddie, Sussex and Greeneville counties have some of the richest titanium deposits in the world. The mine in Dinwiddie was considered a Strategic National Resource for a long time and supplied a lot of the titanium to the military for most of the Cold War.

I-95 was built just inland of where the shoreline would have been due to soil structures were better than the sandy/swampy soils east of the dividing line between Piedmont and Tidewater.