There are a lot of psuedofossils out there. What you are seeing is probably different weathering, either the rock formed with hard and soft spots that weather differently, or it’s been against a surface that caused it to weather in different patterns. Weathering does crazy stuff, from hoodoos to wonderstone.

it’s a fun but smallish museum. Some good collecting in the area though, trilobites, corals, and stromatolites all easily collected and within a couple hours of each other.

The Idaho Museum of Natural History has a great Ray Troll whorl shark exhibit

no enamel, if it is a tooth it’s really weathered.

I’ve seen all the pictures and agree with matthew-gramling. Ironstone or similar, not a fossil.

possible stromatolite, but really depends on where you found it. If you know the location it was collected use macrostrat.org to find the formation, and see if stromatolite makes sense.

I’m guessing botryoidal jasper/chalcedony; not a fossil. nice piece though!

I wouldn’t promise it’s a fossil, but if you like it, keep it. Again though knowing where it’s from can help identify if it’s a fossil or not.

Depending on where found it might be petrified wood, but it’s really hard to say and I’m guessing probably not. Chalcedony for sure, agate-ish in pictures.

is it seemingly lightweight for its size? shape suggests it possibly is, if it seems light then there may well be a cavity inside

I agree it’s probably horn coral

dendrites, not fossil. but very nice ones!

if you want to get to the fish underneath and this hasn’t been sealed a pin will generally flake off the shale and leave the base fossil. be gentle and go slow, but it’d how a bunch of the commercial guys prep things.

looks like greenriver to me, and probably knitia eocaena as they are super common, but maybe alta. http://www.fossilmuseum.net/Fossil_Galleries/GreenRiverFish.htm or https://geology.com/articles/green-river-fossils/fish-fossils.shtml have reasonable photos to compare

I was working on it with @mackenzie-smith if they remember what it was.

It’s not a sponge but similar. The name escapes me but I have one uploaded in my specimens, but I’m mobile and didn’t add it to my gallery so I can’t find the name :/ but if you can look at the specimens I uploaded it’s there.

crazylace agate

agate (rock).