That's a hell of a lot of fossils from such a small area...
I am fascinated by Geology too. I knew some areas inland from where I am had some semi-precious gems and some small pockets of gold (long gone now). When researching with a view to maybe looking for some gems I came across a complete geological synopsis of the greater area. It was all under water a long time back too so a lot of old sedimentary. Then there was a long period of upliftment and volcanic intrusion. 70 or so k's north of here there was a super volcano so there is a large area of basalt up that way.
Years ago when surfing Indonesia, we stayed for a few days at a place called Lake Toba on Sumatra. I just thought it was a large mountain lake (maybe 80k's long and up to 30k's wide with a big island taking up about half that area). I was intrigued by some steep eroded cliffs around a lot of the shoreline. When I looked it up sometime later I discovered that it was a single super volcano. The island was the plug!!!
Keep your eye on Yellowstone...