Fossilized Tree Leaf (IMAGE) McGill University Caption This fossilized tree leaf, are the first of their kind to have been found in the area. Alexandre Demers-Potvin, used the samples he collected to establish that Eastern Canada would have had a warm temperate and fully humid climate during the middle of Cretaceous period. Credit Alexandre Demers-Potvin Usage Restrictions Please credit License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.