This photo gives you a sense of the size of the frond.
Check out this monster. It's the latest acquisition for World Museum Liverpool. It's a 50 million year old palm frond, Sabalites
sp. It was found in Folly Quarry on the Lewis Ranch, near Kemmerer Wyoming City, Western Lincoln County, Wyoming, USA. It's over seven feet tall as you can probably guess looking at the man to the right of this photo
Now for the technical bit from curator, Dr Alan Bowden: The rock formation is the Fossil Butte Member of the Green River Formation, Eocene (50 million years ago). The Green River Formation of Wyoming represents sediment that was laid down in a series of large freshwater lakes. Algal blooms led to a lack of oxygen in the water causing many of the lake’s animals and plants to die, as well as stopping bacterial action on the bottom of the lake. Here, dead animals and plants that would normally have rotted away were preserved in exceptional detail. Deposits such as this provide a rare glimpse into a long vanished world with its spectacular preservation of plant and animal remains. The fossil palm frond shows us that 50 million years ago this was a subtropical environment with lush and exotic vegetation bordering a large lake complex. It was a very different environment from the high mountain desert found in Wyoming today, where temperatures frequently go below freezing with long winter snows.
There are further photos of this fossil on our Flickr page.