One of the more bizarre Stranger quests in Red Dead 2 is A Test Of Faith. Check out this Red Dead Redemption 2 Test Of Faith stranger guide to complete it without much hassle. Collecting these things can a bit much on your own.
Red Dead 2 A Test Of Faith Stranger GuideOne huge tip I am going to give you is to use your Hunter Vision. The bones will shine in yellow if you are near them and it can help you spot ones you might have missed.
I tried to make this list as sensible as I could, but you are going to have to do some riding.
This one is south west of Valentine and can be found on the side of a cliff.
There is a little abandoned oil derelict south east of Valentine. If you use the ladder to get underneath it you will find another dino bone.
This one is slightly south of the oil derelict and you can find it in a near a rock face. Use your hunter vision to spot it easier.