|
At Promontory Butte, on the Mogollon Rim, near Christopher Creek, AZ.
This is a Pennsylvanian/Permian boundary river deposit that has a
mixture of wetter coal swamp plants like ferns and horsetails and drier
"upland" elements like conifers preserved in a grey shale. It's
interesting because it shows this ecological transition that occured
around 300 million years ago when the conifers first started to become
important with drier conditions.
|
|
At Yakima Canyon, central Washington state. Petrified fossils from here
are 15 million years old (midle Miocene) and include petrified ferns,
conifers, oaks and other hardwood trees, mostly related to modern
genera. The difference is that today this area is desert scrub, not
hardwood forest. The fossils were preserved by minerals from volcanic
eruptions.
|
|
|
This is a middle Miocene site(also around 15 million years old) in
the Virgin Valley, northwestern Nevada. By then Nevade had already
started climatic changes toward present day dry conditions while the
Yakima site in Washington, of the same age, was still a nice forest.
|
|
|
At Fossil Creek, near Strawberry, AZ. Fossils of
Pennsylvanian/Permian boundary age (300 million years), similar to the
Promonotory Butte fossils at site in fig 1.
|
|
These are compressed leaves from the Miocene of the northern Czech
Republic that occur along with large coal deposits. On this slab you can
see some sweet gum leaves (the ones with the pointy tips) and some bald
cypress conifer twigs (the ones with the little needle-like leaves).
|
|
|
Another slab from the Miocene of northern Czech Republic. The plant
on the surface with all the little roots is an aquatic floating plant.
|
