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These are called crinoid columnals

That is an orthocone shell, however its shape has left me confused more than once. you see, l have a small box filled with orthocone shells. Some are normal, but some are like that, looking as though two skinny shells joined together along their length. My current theory about why it looks like that is that the shell was crushed under the layers of sediment. Try a simple home experiment to see how this works. An empty toilet paper roll represents an orthocone shell. Hold it in your hands, and do a sort of maneuver like when you open an egg, where you push your thumbs into the midline. It would definitely be better to provide illustrations for this, and l doubt you will be able to comprehend my terribly dictated instructions, but you’ll know you succeeded when the hole in the roll gets a figure 8 shape- just like the shell 😉

this message took a while to type, so l just saw vperez’s comment. that is also a very likely possibility, since l always had a slight suspicion by the small size of my specimens. Maybe they were crinoid pieces all along!

I’m more inclined towards 2 crinoid columnals since the individual chambers of an orthocone are concave/convex. It looks straight in this picture. Also, orthocones will start constricting into a cone shape, whereas crinoid columnals are uniform in thickness.

The diameter of a Canadian 2 dollar piece is 28mm.