Here is the full list of all 47 Fossil Hunters achievements.
Pick up the Sammy rock and bring it to the elevator
Collect all other achievements
Complete all the Collector's requests
Collect all Abyss journal entries
Collect all journal entries
Collect all golden idols
Build 5 colossal skeletons
Collect all Magma Chamber journal entries
Unlock the bridge shopkeep
Make 100 skeletons
Collect all Mushroom Caverns journal entries
Unlock the support shopkeep
Prevent a death with a dodge roll
Use 20 bridges
Submit a skeleton with every piece damaged
Use 20 supports
Drop 50 fossils in pits
Collect all Digsite journal entries
Transport 12 or more items with the elevator
Play as each of the Fossil Hunters
Finish the game
Unlock all schematic doors
Pick up an idol from the treasure hoard
Have all three power-ups active at once
Submit 50 clean & pristine skeletons
Build 10 huge skeletons
Make 50 skeletons
Unlock the dynamite shopkeep
Get all destruction achievements
Have a fossil smashed by a lavamander
Drop a golden idol in a pit
Build 15 big skeletons
Die in a pit 100 times
Have a fossil covered in moss
Use 20 dynamite barrels
Use 20 lamps
Have your multiplayer friends drop out
Unlock the lamp shopkeep
Collect a golden idol
Have a fossil eaten by a crawler
Make 10 skeletons
Have a fossil smashed by a cave-in
Unlock a schematic door
Rearrange the furniture in the lab
Make a skeleton
Leap the maximum distance
Bring 20 new objects into the lab