| Here is a complete leaf from a species of alder, Alnus jarbidgiana, the most common fossil plant variety encountered in the upper Eocene Dead Horse Tuff at Copper Basin, Nevada. The specimen is 38 to 39 million years old. |
| Here is a complete leaf from a species of alder, Alnus jarbidgiana, the most common fossil plant variety encountered in the upper Eocene Dead Horse Tuff at Copper Basin, Nevada. The specimen is 38 to 39 million years old. |