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of images of Arizona fossils is the result of decades of time
well spent in the field around our great State. We have spent
thousands of hours collecting, documenting and taking photos
of fossils covering a wide range of ages from Precambrian to
Holocene. In addition, countless of hours have been spent at
organizing, identifying (if possible) and properly storing and
labeling the specimens. Fossils that are too large or were not
removable have been extensively photographed in the field. Lets
start here now with Arizona's earliest fossils, from the Precambrian
limestones, cherts and shales of the Mescal Limestone in the
north central part of our State.|
Click image to go to Write up.
The Mescal Limestone of Central Arizona and the base of the Mogollon
Rim contains locally abundant stromatolites and algal mats. Though
"stroms" are considered to be trace fossils, they represent
the remains of the largest life forms present 1.2 Billion years
ago in the Proterzoic Era.|
The Cambrian fossils
of Arizona occupy a special place in our hearts, the unique and
primitive lifeforms are our favorite members of our collections.
We have spent more time in the Cambrian than any other time period,
with the exception of the Mississippian. The Tonto Group to the
North and Cambrian in south eastern Arizona are from the same
ocean - but differ in naming and on some of the fossil types
found in each formation. To keep organized, I will cover these
formations separately, from the shallow tidal flats of the Tapeats
and Bolsa Quartzite, to the deep water limestones of the Muav
and Abrigo formation. Here is a listing of the Cambrian formations
we will be discussing here in Arizona:
- Mogollon Rim through to the Grand Canyon:
1. Tapeats Sandstone (Beach, tidal flat, shallow water)
2. Bright Angel Shale (Muddy sediments including deeper water shales, mudstones, claystones)
3. Muav Limestone (Deep water limestones)
South Eastern Arizona - South of Tucson to South eastern border.
4. Bolsa Quartzite (Beach, tidal flat, shallow water)
5. Abrigo Formation - Shale Member (Muddy sediments including deeper water shales, mudstones, claystones)
6. Abrigo Formation - Limestone Member (Deep water limestones)
Click image to go to article
of the Mogollon Rim / Payson / Grand Canyon Area.
From the south
limits of the Town of Payson, to the East Fork of the Verde River
north of town, the Tapeats outcrops frequently and is the basal
sedimentary unit in the region overlaying the 1.8 billion year
old Pre Cambrian granites. In most areas it is less than 50 feet
thick, and contains a few sedimentary structures and strongly
graded bedding which highlights it origins - Near shore tidal
flat and sand bar lithology. We are quite familiar with this
formation - Our house is right on the outcrop! Fossils are very
sparse and consist of primarily trace fossils.
Fort Apache Limestone.
Click image to go to article
Angel Shale of Northern Arizona.
are led to believe that the Lower Middle Cambrian Bright Angel
Shale can only be found in the depths of the Grand Canyon National
Park, and therefore is not open to collecting for the general
public. After much research spanning years pouring over old -
and nearly unobtainable geologic maps, professional papers and
Bulletins, we found that this is not the case. There are half
a dozen small areas far outside the Canyon (south), and isolated
outcrops in the Juniper Mountains in Northern Arizona. We spent
over a year finding and evaluating these outcrops - when accessible,
and found two in particular that were highly fossiliferous. Besides
hordes of Cambrian trace fossils, we found a plentiful but low
diversity of fauna similar to the Burgess Shale in British Columbia,
and the Chenchang Fauna in China. Phyllums include at least half
a dozen species of Trilobites, Hyalithids, inarticulate Brachiopods,
a colonial hydrozoan like animal, and trace fossils from arthropods,
mollusks, and annelids.
(Anisopyge inornata Trilobite)
Click image to go to Article
The Fort Apache Limestone East of Payson, Az.
Leonardian in age,
this Permian marine transgression onto the Schnebly Hill formation
is a very thin facies with few if any fossils. However, the more
east you go towards the reservation in which it is at a maximum
thickness of 100 feet, the more fossils you will find. One location,
near the Highland Trail along Highway 260 is the last outcrop
available before it is under the surface on the Rim until the
reservation a hundred miles distant. There, you can find micro
fossils that can be retrieved by acid reduction of the limestones.