Without looking at the spores under a microscope, the best you can do is with a mushroom ID guide geared toward the region in which you live. Sometimes you can only narrow a sample mushroom down to a handful of species, even with multiple field guides and references. However, if none of those species are fatally poisonous, you might as well eat a small piece and see what happens (that's what I used to do, at least).
If you live near a university, the resident mycologist (if there is a mycology department) would probably be more than happy to help you identify them (He will likely know all of the local species by heart and by eye).
Good luck. Sorry I could not be of any real help in the ID.
