There was a place I discovered in some woods in Illinois, where a spring came out of the ground and a large patch of rocks was exposed. The entire area of rocks, perhaps the size of a tennis court, was just a mass of fossilised crinoids rather like in those photos. There were also tons (probably literally) of loose crinoid bits all over the place, like little polished disk-shaped agate beads. I collected several bags of the loose bits, but I think I’ve probably lost them all since then.
If I ever pass through Illinois again, I might be tempted to find the place once more. I still remember the general area where it was. There was a big housing development nearby, though, so I wouldn’t be surprised if it has all been built over during the intervening years.