I really do not feel I can say what I think this is, as last time I jumped in, made a mess . Okay I found this fossil about five years back in Cheshire , UK . I was walking in a field , I had my metal detector, I could see a farmer on a tractor. Having walked towards him , he put his head out of his door , shouted yes , I just pointed to the ground and to the detector. I made a sweeping motion with my detector. The farmer shouted over his tractor engine yes, do what you want. After detecting for a time, I noticed the stones looked kinda strange and started putting some in my pockets . after a short time my coat was heavy, had to get to my car , I found a few cool stones by the road, including this one.