The Morrison Formation - Fossil Ecosystems of North America: A Guide to the Sites and their Extraordinary Biotas - page 142

conditions in the south. It is in the mid-
west states of Colorado, Utah, and
Wyoming, where the Morrison Formation
represents mostly fluviatile and lacustrine
deposits, that the richest finds have been
made. Here, flash floods deposited
literally tons of bones ( 143 ) in a
Concentration Lagerstätte which gives a
detailed insight into a late Jurassic
terrestrial ecosystem that includes not only
some of the largest dinosaurs known, but
also some of the other land animals which
coexisted alongside the dinosaurs,
including the most diverse Mesozoic
mammal assemblage yet known.

his work on hadrosaurs from Kansas. In
the same year Lucas found bones from
the same horizon near Canyon City, which
he sent to Edward Drinker Cope at
Philadelphia, who had described some of
the first ceratopsian dinosaurs from
Montana.
Marsh and Cope were already bitter
enemies due to an earlier dispute over
Cope's description of a fossil reptile which
Marsh had shown to be erroneous.
Immediately, a frantic race began between
the two men to describe the numerous new
dinosaurs that were being collected.
Cope's specimens from Canyon City were
larger and much more complete and at
first he had the upper hand, but later the
same year (1877) new discoveries were
made in equivalent beds at Como Bluff,
Wyoming, and this time Marsh was first on
the scene.
Como Bluff, near Medicine Bow,
Wyoming, is a low ridge, approximately
16 km (10 miles) long and 1.6 km
(1 mile) wide formed by a north-
east-south-west trending anticline with a
gently dipping southern limb and a
steeply dipping northern limb. The
southern limb is capped by the highly
resistant Cloverly Formation of the
lowermost Cretaceous, while the northern
limb exposes the underlying beds of the

H ISTORY OF DISCOVERY OF THE
M ORRISON F ORMATION
The story of the discovery of the Morrison
Formation dinosaurs has become known
in American paleontological folklore as
'The Bone Wars' and is the story of a
bitter rivalry between two of America's
leading paleontologists of the late
nineteenth century. It began in 1877
when two schoolteachers, Arthur Lakes
and OW Lucas, independently discovered
rich remains of dinosaur bones in
Colorado. Lakes sent his fossils, which he
had found near the town of Morrison, to
Professor Othniel Charles Marsh of Yale's
Peabody Museum, who was well known for

143

143 Fossil Cabin Museum,
Como Bluff, Wyoming.
Dinosaur bones are so common
that they are used as a building
material.