The fossil remains from Axel Heiberg Island are an outstanding example of preservation. These plants were not permineralized (replaced with silica). They still contain their original carbon based material and the wood from the trees can still be burned.
The picture to the left is an example of the outstanding preservation. These cypress needles, found in a forest floor litter portion of the Axel Heiberg Island deposits, are over 40 million years old, and because of the incredible way they were preserved, they look better than most year old forest floor litter.
These flora were not permineralised because of the way they were buried. While they were still living in the Eocene, the forests were covered by silt filled flood waters. The silt blocked out the mineral rich water and protected the flora from being replaced with the silica in the water.
These great floods were not a yearly occurence. Instead they occured perhaps every 10,000 years. It was this flooding that preserved what the forest was like. After the floods, a new forest would grow on top of the old one. There were at least 19 such events on Axel Heiberg Island.