LAYERS PUZZLE
LAYERS PUZZLE
SOLVE A SEDIMENTARY
SOLVE A SEDIMENTARY
Did you know that the
history of life on Earth
is told through rocks?
Over millions of years, sediments
such as sand and silt were laid
down and compressed to form
sedimentary rock layers. They
preserve a record of ancient land-
scapes, climates, and organisms.
Scientists often determine the
correct sequence of sedimentary
rock layers using the fossils found
within them. They compare the
fossils to fi gure out if two layers
are from the same geologic time
period, or if one layer is older
than the other.
Try reconstructing the layers
below using the same strategy!
1. Photocopy and cut out the fi ve strips of paper
Each strip represents a sedimentary rock layer
formed during a certain time period.
2. Put the layers in correct order
Begin by placing B, the “oldest layer,”
on the bottom. Then decide which
layer comes next. It will have some
of the same organisms as the older
layer and some new ones. (Hint: Organisms do not disappear for a layer
and then reappear.) Place it above. Continue until the layers are in order,
with the youngest at the top. Check your answers and write the time
period on each layer.
Look at the fossils within each layer. What plants and animals lived
during the same time period? Then compare the layers to explore the
changing plant and animal groups throughout Earth’s history. Which
organisms survived from one time period to the next? Which ones went
extinct? Could
Tarbosaurus
have hunted
Seismosaurus
? What organ-
isms survived the mass extinction at the end of the Cretaceous Period?
Explore More!
Answers: Order of layers from top to bottom: D (Quaternary Period, 2 million years ago to present), A (Tertiary Period, 65-2 mya),
C (Cretaceous Period, 145-65 mya), E (Jurassic Period, 200-145 mya), and B (Triassic Period, 250-200 mya)
Dinosaur fossils
have been
discovered on
every continent,
even Antarctica.
FUN
FACT
OLDEST LAYER
A
B
C
D
E
gingko
gingko
gingko
gingko
gingko
dragonfl y
dragonfl y
dragonfl y
dragonfl y
dragonfl y
sharks
sharks
sharks
sharks
sharks
dyrosaurs
birds
birds
birds
birds
fl owering
plants
fl owering
plants
fl owering
plants
horses
horses
ammonites
ammonites
ammonites
icthyosaurs
icthyosaurs
icthyosaurs
pterosaur
pterosaur
pterosaur
Postosuchus
Coelophysis
Effi gia
Tarbosaurus
bataar
Seismosaurus
Homo sapiens
Stegosaurus
dyrosaurs
© 2007 American Museum of Natural History. All rights reserved.
