The Morrison Formation - Fossil Ecosystems of North America: A Guide to the Sites and their Extraordinary Biotas - page 143

uppermost Jurassic, which have since
been named the Morrison Formation
after the classic locality near Denver. It
was in these latter beds that the rich
dinosaur fauna, mainly of giant
sauropods, was preserved.
The discovery at Como Bluff further
fuelled the 'Bone Wars'. It was made by
two workers on the transcontinental
Union Pacific Railroad, which was then
being driven through southern Wyoming
to exploit the region's extensive deposits
of coal (Breithaupt, 1998). In July 1877
William Edward Carlin, the station agent
at nearby Carbon Station, and the section
foreman, William Harlow Reed, wrote to
Marsh informing him that they had
discovered some gigantic bones of what
they thought to be Megatherium (the
Pleistocene ground-sloth), and offered to
sell the fossils to Marsh and also to collect
further specimens if required. They
signed the secret letter with their middle
names, Harlow and Edwards, to cover up
their identities. Four months later Marsh's
representative, Samuel Wendell Williston,
arrived at Como Bluff to survey the site
and to pay Carlin and Reed their costs.
(A previous cheque made out by Marsh to
'Harlow and Edwards' could not be
cashed since these were not their real
names!)
Williston immediately informed Marsh
of the richness of Como Bluff and
transferred his collecting crews from
Colorado to the new site. Carlin and Reed
continued to work for Marsh, the latter
eventually becoming the curator of the
Geological Museum of the University of
Wyoming in Laramie, and a respected
paleontologist. Not wishing to be outdone,
Cope moved his crews to Como Bluff,
eventually persuading Carlin to work for
him. The feud extended into field
operations and skirmishes between rival
camps often broke out. Breithaupt (1998)
reports spying on rival quarries, smashing

of bones to prevent the opposition
collecting them, and sometimes even
'fisticuffs'!
Over the ensuing years, however, a
huge number of new dinosaurs were
discovered including the carnivore
Allosaurus , the strange, plated dinosaur
Stegosaurus , and the largest sauropods
then known, such as Diplodocus and the
notorious Brontosaurus (now known as
Apatosaurus ). Alongside the dinosaurs the
Morrison also yielded the most important
fauna of Mesozoic mammals yet
discovered.
The rivalry continued until Cope's
death in 1897; Marsh died in 1899. By the
end of their careers Marsh had described
75 new species of dinosaur, of which 19 are
valid today, while Cope had described 55
species of which 9 are valid today. The
Morrison Formation, now known from
twelve different states in North America
( 142 ), remains one of the world's most
prolific dinosaur 'graveyards' and its fossils
can be seen on display in museums all over
the world.

S TRATIGRAPHIC SETTING AND
TAPHONOMY OF THE M ORRISON
F ORMATION
The Morrison Formation, traditionally
divided into four members (Gregory 1938),
was restricted to a two-member division
by Anderson and Lucas (1998): an upper
Brushy Basin Member and a lower Salt
Wash Member ( 144 ). It has been dated
radiometrically and on microfossil evidence
as Kimmeridgian to early Tithonian (Upper
Jurassic; approximately 150 million years
ago) and its outcrop along the Front Range
of the Rocky Mountains ( 145 ) covers an
area of more than 1.5 million square km
(0.6 million square miles). The thickness is
highly variable, but at Dinosaur National
Monument in Utah it is approximately
188 m (620 ft).