Explore Milwaukee County (Click on picture) Milwaukee County, created in 1834 as a territorial county, is derived from a Native American word Mahnawaukee-Seepe meaning gathering place by the river.. Located in southeast Wisconsin, the county seat is Milwaukee.
The Cretaceous-Tertiary extinction event, or the K-T event, is the name given to the die-off of the dinosaurs and other species that took place some 65.5 million years ago. For many years, paleontologists believed this event was caused by climate and geological changes that interrupted the dinosaursâ food supply.
Plesiosaurs became extinct 65.5 million years ago, probably for the same reason the dinosaurs died out. The generally excepted theory is that an asteroid, 6 miles in diameter, crashed into the Yucatan Peninsula and threw dust into the atmosphere. The dust layer blocked the sun for months, killing plants and plankton.