Historical Geology Understanding Our Planet\'s Past

Sharks breathe by drawing water in through the mouth, passing it over the gills, and expelling it through distinctive slits behi ...

gastropods. The more advanced articulate brachiopods appeared in the Devonian and became important stratigraphic markers for the ...

during the Devonian. They are among the most common fauna and impor- tant for long-range rock correlations of this period. The c ...

by the Tertiary.They were related to the modern squid and octopus and pos- sessed a long, bulletlike shell.The shell was straigh ...

dwindle when the crisis subsided and other groups recovered.Their prosper- ity during the late Devonian signifies that less fort ...

In contrast, cold-adapted animals living in Arctic waters fared quite well. Much of Gondwana was in the Antarctic during the Dev ...

of the impact deposits. The evidence suggests that meteorite bombardments might have contributed to many mass extinctions throug ...

the late Devonian more than 370 million years ago, when amphibians were just beginning to craw out of the sea onto the land.The ...

Lobe-finned fish breathed with gills. Unlike other fish, they also breathed with lungs. These were the predecessors of modern lu ...

Free ebooks ==> http://www.Ebook777.com siderable distance before finding another suitable home. It breathes with prim- itive ...

The middle Devonian Old Red Sandstone, a thick sequence of chiefly nonmarine sediments in Great Britain and northwestern Europe ...

Figure 104Location of the Old Red Sandstone in Northern Europe. Figure 105A limestone formation of the Bend Group of the Sierra ...

The second half of the Paleozoic followed a Silurian ice age, when Gond- wana wandered into the southern polar region around 400 ...

Evaporite deposits generally form under arid conditions between 30 degrees north and south of the equator. However, extensive ev ...

T his chapter examines the evolution of the amphibians in the great coal swamps of the Carboniferous period and follows the buil ...

the end of the period, the first reptiles emerged and displaced the amphibians as the dominant land vertebrates. THE AMPHIBIAN E ...

land offered no large animals to eat, and vertebrates had not yet evolved the capacity to consume plants. Therefore, the only fo ...

water and half the time on dry land. It was dog sized, with a broad, flat, fish- like head and a tail topped with a small fin, a ...

Amphibian footprints were quite abundant during Carboniferous period but less so in the Permian, owing to the takeover by the re ...

Free ebooks ==> http://www.Ebook777.com much like a forest of telephone poles. Only near the end of their lives did the lycop ...