I found a good but simple explanation on this blog -> http://historyoftheearth-fossils.blogspot.com/search/label/page%202
No the only way to get the other fossil is trade the Pokemon that was inside from another game to yours.
Fossils can be formed by:MummificationPetrificationDesiccationRelated question on Answers.com:How are fossils formed?
In a way,yes.
Archaeologists use fossils to scan the way of living of the past people.
The way fossils are formed in very dry places is called mummification. Amber is a hardened tree sap, yellow to brown in color, and often a source of insect fossils.
It supports the continental drift.
Another kind of fossil is a mold or cast fossil, which forms when an organism's remains decay and leave an impression in the surrounding sediment that is later filled with minerals. Another type is a trace fossil, which is evidence of an organism's activity, like footprints or burrows, preserved in rock.
The only way to get both Generation 5 fossils as in the Cover Fossil which is also the Tirtouga Fossil and the Plume Fossil, also known as the Archen Fossil, you will need to trade with another player in order to receive the other Fossil. Fossils in Pokémon Black can be attached to any Pokémon that you're trading.
Get all of the Pteranodon fossils. You get those the same way as normal fossils. Missions and exploring and such.
It is estimated that the very first fossils were found 3 billions years ago. There is really no way to know if the dates were not recorded.
sedimentary rock my guy fossils fossils fossils fossils fossils fossils fossils fossils fossils fossils nbut u cant see thrm lel
Imprint fossils, Mineralized fossils, frozen fossils, fossils in amber, and cast fossils.