SUPERB OXYTROPIDOCERAS AMMONITE
- Goodland Formation - Cooke County, Texas, USA
PERIOD (EARLY UPPER ALBIAN STAGE) : 101 million years ago
are important index fossils—that
is, they often link the rock layer in which they are found to specific
geological time periods. This is especially true of this rare and
exquisite example of the Cretaceous species of ammonite called Oxytropidoceras
powelli. These ammonites, found in Texas, USA are used by
geologists and paleontologists as a zone marker for the Early Upper
Albian Stage of the Cretaceous identified to 101 million years
delicate shelled creature, usually these fossil ammonites are found
deformed by pressure or partially crushed. Probably one of the
most aesthetic ammonite species found in North America, its graceful
lines and the surrealistic gentle curves in its chamber detail are most
beautiful. This detail is natural and has not been artificially
created by carving the entire surface as many Moroccan ammonites in the
marketplace have been subjected to. This
specific specimen is one of the most complete and nicest examples we
have seen to
date and is the only one we have to offer at this time and the second
one we have ever listed!
possesses NO REPAIR
AND NO RESTORATION.
Spectacular color is natural.
recommend this excellent example. Specimens from this species and
the USA are NOT common and not mined commercially compared to the much
more prevalent Moroccan and Madagascar types always seen for sale.
This complete, very high grade specimen hails from the same time period as
many of North America's famous dinosaurs and is a superbly preserved as
well as a wonderfully aesthetic display fossil.
are extinct members of the Cephalopod class.
Modern members include nautilus, squid and octopus.
They first appeared during the Silurian Period (435 million to
410 million years ago) and were abundant and widespread in the seas of
the Jurassic and Cretaceous periods (175 million to 65 million years
ago). Ammonites are important index
fossils—that is, they often link the rock layer in which they
are found to specific geological time periods.
Ammonites varied greatly in size.
as 2 cm (0.75 in) in diameter. During the Jurassic and Cretaceous
periods, ammonites evolved more streamlined shells for swimming and the
structure of the shell became stronger. Different shell shapes emerged
as well, such as snail-like or uncoiled.
The shells of
had hollow chambers separated by walls called septa. A tube called the siphuncle, connected the body with the
chambers allowing the animal to fill them with water or air, changing
its buoyancy in order to rise or drop in the ocean.
the last and largest chamber was occupied by the living animal.
probably lived for one to six years, with the majority living two to
four years. They fed on plankton (tiny free-floating organisms), sea
lilies, and smaller
orthoceras. Although many fed off the ocean floor, others may have
caught plankton while floating or swimming via jet propulsion,
expelling water through a funnel-like opening to propel themselves in
the opposite direction.
Because ammonites lived
exclusively in marine environments, their presence also indicates the
location of prehistoric seas.
OF THE MOST VISUALLY PLEASING SPECIES WITH MAGNIFICENT NATURAL DETAIL!
WE HAVE HAD OF THIS SUPERIOR QUALITY AND THE LARGEST - RARE
IN THIS CONDITION!!!
Item - One Only