Here is the full list of all 20 Prehistoric Tales achievements.
For winning 40 battles.
For eliminating 250 dinosaurs.
For finding 25 artifacts and rare items.
For winning 20 battles.
For reaching level 25.
For 200 exchanges with traders.
For finding 15 artifacts and rare items.
For using 70 spells in battles.
For rescuing the valley from the invasion of greenskins.
For building 40 constructions in your settlement.
For reaching level 15.
For using 30 spells in battles.
For 70 exchanges with traders.
For winning 7 battles.
For building 15 constructions in your settlement.
For reaching level 10.
For making friends with a little greenskin.
For starting trade relationships with neighboring tribes.
For collecting 120 plants.
For finding the arena of ancient battles.