Fossil evidence1[1]

Fossil Evidence

Mesosaurus

An odd, fresh-water dwelling reptile (not a dinosaur. It was a lightly-built, four-legged animal with an elongated head and snout with nostrils near its eyes. It had a flattened tail that was probably used for swimming. It was

about 1.5 feet (45 cm) long. This carnivore probably ate fish and

shrimp, catching them with its mouth.

Mesosaurus

• Why is he evidence of drifting continents?

Lystrosaurus

•

This historic animal was about the size and weight of a modern pig. The structure of the skull, with the nostrils and eye sockets placed

near the top of the head, the snout turned down at the tip and the teeth and jaws placed low, all

suggest that Lystrosaurus found food in the water, in much the

same fashion as the living hippopotamus.

Lystrosaurus

• Why is he evidence of drifting continents?

Cynognathus

•

• Cynognathus was approximately as large as a modern wolf and, like the wolf, was an active predator. The body of Cynognathus was not massively constructed. The tail was short, and the limbs were tucked well under and close to the body, providing the potential for rapid and efficient locomotion.

Cynognathus

Why is he evidence of drifting continents?

Glossopteris

•

• The large number of leaves found preserved, and the character of the deposits in which these are found, suggest that glossopteris were deciduous, losing their leaves in the autumn, and growing new leaves in each spring.

Glossopteris

• Why is it evidence of drifting continents?

Glacial Evidence

• Evidence within climate data

• On the left is a photograph of Muir Glacier taken on August 13, 1941, by glaciologist William O. Field; on the right, a photograph taken from the same vantage on August 31, 2004, by geologist Bruce F. Molnia of the United States Geological Survey (USGS).

On the top is a photograph of McCall Glacier from July of 1958 taken by

Austin S. Post; on the bottom, a photograph taken from the same

vantage on August 13, 2003 by Matt Nolan.

Rock sequences in South America, Africa, India, Antarctica, and Australia show similarities. Wegener showed that the same three layers occur at each of these places. The bottom (oldest) layer is called tillite and is thought to be a glacial deposit. The middle layer is composed of sandstone, shale, and coal beds. Glossopteris fossils are in the bottom and middle layers. The top (youngest) layer is lava flows. The same three layers are in the same order in areas now separated by great distances. Wegener said that the rock layers were made when all the continents were part of Pangaea. Thus, they would have to have been formed in an area that was later broken and drifted apart.

Fossil Evidence