In X and Y, The Fossils can be revived in the Fossil Lab in Ambrette Town. !!
Here are all the fossil Pokemon (as of November 2015):AerodactylAmauraAnorithArchenArcheopsArmaldoAurorusBastiodonCarracostaCradilyCranidosKabutoKabutopsLileepOmanyteOmastarRampardosShieldonTirtougaTyrantrumTyrunt
No, you can only pick one per version. You will need to trade for the other fossil Pokemon to complete the collection in Kalos. The Sail Fossil is Amaura, the Rock/Ice-type Pokemon, and the Jaw Fossil is Tyrunt, the Rock/Dragon-type Pokemon.
Make sure you have put the fossil in you bag. Press Y and select treasures select the fossil and select put into bag. Then you will be able to exchange it for a Pokemon.
either: cast fossil petrified fossil imprint fossil trace fossil
Cover Fossil is Tirtouga. Plume Fossil is Archen.
You cannot get Skull Fossil or Armor Fossil in Pokemon HeartGold.
root fossil is lileep claw fossil is anorith
Tirtouga from the Cover fossil, and Archen from the Plume fossil.
Kabuto is in the dome fossil and Omanyte is in the helix fossil.
At the museum in Oreburgh City there is a man that will get the pokemon out of the fossil.
The Dome Fossil can be revived into the pokemon kabuto.