You will find the Pokemon you can extract from fossils and other info in the link below.
http://bulbapedia.bulbagarden.net/wiki/Fossil
List:
Helix Fossil - Omanyte
Done Fossil - Kabuto
Old Amber - Aerodactyl
Root Fossil - Lileep
Claw Fossil - Anorith
Skull Fossil - Cranidos
Armor Fossil - Shelidon
Cover Fossil - Tirtouga
Plume Fossil - Archen
In HeartGold/SoulSilver, these Pokemon can be revived at the Pewter Museum of Science.
*= only obtainable in Generation V. HeartGold is Gen IV, so they cannot be obtained.