The Hell Creek Formation - Fossil Ecosystems of North America: A Guide to the Sites and their Extraordinary Biotas - page 166

the well-known velociraptorids as seen in
the film 'Jurassic Park'. Both were less
than 2 m (6 ft) long, but possessed the
vicious, retractable, sickle-shaped 'killing
claw' on the second toe. Similar to these
was Troodon , a lightly-built, bird-like
predator, with binocular vision and also
possessing the 'sickle claw'.

Hell Creek Formation. These huge
quadrupedal herbivores were up to 9 m
(30 ft) long and weighed up to 9 tons.
The well-known Triceratops ( 173, 174 )
had a massive head supporting three
long horns (up to 1 m [3.3 ft] long), a
solid neck frill rimmed with bony bumps,
and a narrow parrot-like beak for cutting
through thick vegetation.

Ceratopsids
Enormous herds of ceratopsids were the
very last dinosaurs to inhabit this region
before the meteorite impact finally
wiped them out. Their remains are the
most abundant dinosaur fossils in the

Hadrosaurs
These heavily-built, bipedal/quadrupedal,
ornithopod dinosaurs (see Chapter 9,
p. 151) are known as the 'duckbills' due to
their broad, flat, toothless beaks. They are

173

173 The ornithischian dinosaur
TriceratopsBHIGR. Length
9 m 30 ft.

174

174 Reconstruction of
Triceratops.