All 30 Dinosaur Bones in RDR2

Dinosaur Bones are 30 fossil fragments scattered mostly across the northern and western regions of the map — Ambarino, New Hanover and West Elizabeth. They are unlocked by finding Miss Deborah MacGuiness, a paleontologist camped on a hill northeast of Flatneck Station in New Hanover, which starts the stranger mission "A Test of Faith". After that, every bone you find can be mailed to her from any post office rather than delivered in person, so there is no need to backtrack to her camp. Rewards arrive in stages rather than all at once: the first bone you mail returns a Quartz Chunk used in talisman crafting, your 15th returns a small statue, and mailing all 30 earns an invitation to her ranch at Firwood Rise in Cumberland Forest, where she gives you the Jawbone Knife. None of the bones are missable and they can be collected in any order, at any point after the stranger mission unlocks, including after the story ends.