Equip your Doedicurus with a saddle, pick it up with an Argentavis and fly near rocks as it automatically harvests the stone as you fly. Level up the melee damage to harvest more stone with each swing. Level up your Argentavis’ weight capacity be an insane stone harvest team.
I just drop this guy by a rocky spot right by my base and set her on wander (and attack target in case he needs to defend herself) and she runs around collecting rock! Then I pick her up with my argey and bring her to a storage box in my base so I can transfer the rock then I drop her back out there so she can keep harvesting