One of the challenges scientists face in reconstructing the composition of the atmosphere in Earth is geological history Lack of available samples In recent years  alot of people are starting to look at Amber and they think that compared to other organic materials  The chemical and isotopic information preserved in amber has remained almost unchanged over the long geological age
Amber was born mainly in the Eocene epoch between forty million and sixty million years ago  Other years did not form amber
 So it could be used to show the global atmospheric composition at different times