In addition to frozen animals obtained from Siberia, a large number of fossils preserved in amber has also been discovered in Russia. These come from what's known as Baltic amber, found in a wide area from Berlin in the west to the Ural mountains in the East. The great majority of Baltic amber dates from the Eocene Period (54 to 37 million years ago).
A large part of this amber lies in the Samland region, currently within the borders of Russia, and is found at an average depth of 25 meters (82 feet) to 40 meters (131 feet) beneath the surface. The stratum containing the amber is known as "blue earth." Each 1000 kilograms (2204 pounds) of soil contains approximately 1 kilogram (2.2 pound)of amber, and only one part in every few hundred contains an inclusion.
The color of the amber, its formation and certain other physical characteristics vary, according to the period when it was formed and the type of tree it came from. The oldest known amber specimens date from the Carboniferous Period (354 to 290 million years ago). Amber from this period is most frequently found in the U.S. and Great Britain.
In order for inclusions to appear inside amber, two very important and consecutive processes take place once the living thing has been trapped in the resin. The first is hardening, due to cold or dryness. The second is the decay of the tissues of the creature trapped inside the resin. Fluids released during the course of this decay process assume a special structure by mixing with the resin fluid. The creature's body is preserved inside a bubbly structure just like a balloon. In order for resin to transform into amber, it must go through a great many chemical and geological stages.
For scientists, inclusions in amber represent a major sphere of activity. Specimens of many living things get trapped at the moment of carrying food back to the nest, in a state of defense, trying to camouflage themselves, attempting to protect their young or releasing chemical substances to neutralize aggressors. And all these specimens represent proof that the characteristics possessed by living things have remained unchanged over millions of years-in other words, that no such process as evolution ever took place.