Looks to be a sand stone with concretions of some sort. Might even be another mineral like selenite that got frozen in the sediment. My thoughts but it does look neat.
Right on. To me I'd guess a petrified chunk of skin But what would I look for?? Cell structure? N what ya mean by organic fossil?? Sorry for all the questions just tryin to figure a few things out
With the other views I can add that it may be limestone as well. I dont see anything that would indicate that it has fossils as the nodules appear to be somewhat random in shape. Closer views may help there. Try putting a bit of vinegar or other mild acid on a test area and see if there is any reaction. Also you can try scratch testing for hardness and look at the material from the test to see if it has a gritty or grainy texture like fine sand.