Page 35 - DINOSOUR ATLAS

north america
Hell Creek #ROOKED
#REEK "AY

&ORT 0ECK ,AKE (ELL #REEK "AY
As the missouri river flows through the east of Montana, it cuts 0ETERSON
0OINT
into a series of ancient rocks known as the Hell Creek Formation.
The deep layers of sandstone, siltstone, and mudstone were formed
during the Late Cretaceous Period, about 65 million years ago. (ELL #REEK
At that time the area was a low-lying floodplain crossed by &ORMATION
rivers, lying along the coast of a now-vanished sea. Many
species of dinosaur and other animals lived and died here. - / . 4 ! . !
Locked within the rocks of the Hell Creek Formation is one of
the world’s major dinosaur graveyards. It was here, in 1902, u site location
that the first Tyrannosaurus rex specimen was found, along Hell Creek is a vast, arid region in the
with other notable discoveries. eastern part of Montana.

edmontosaurus
Slow-moving Edmontosaurus was a
hadrosaur, or duck-billed dinosaur.
troodon triceratops
Many duckbills lived in Hell Creek,
The creek teemed with small, agile Ceratopsians (horned dinosaurs) were the feeding on the ample supply of plants.
dinosaurs, such as Troodon. Armed with area’s most abundant dinosaurs. Triceratops
keen eyesight and sharp, grasping was the largest member of the group.
claws, they were efficient hunters.

brachychampsa
Late Cretaceous crocodiles lay in
wait for their prey, just as their
descendants do today.
giant dragonfly
Winged insects, such as
dragonflies with 8-in Helopanoplia
(20-cm) wingspans, had a wide,
buzzed through the air. flat shell

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