Seismosaurus: This big guy may not have been the heaviest dinosaur, but it was certainly one of the longest land animals that has ever lived. It stretched almost one hundred and fifty feet from tail-tip to snout and weighed almost as much as fifteen full-grown African elephants. Surely this creature shook the earth as it lumbered across the ancient terrain.

Genus Name: Seismosaurus ("earth shaker lizard") 
Type Species: * S. hallorum (Gillette, 1991) 
Length: about 150 feet (45 meters) 
Weight: 30-70 tons 
Time: 155-145 million years ago (Late Jurassic) 
Place: New Mexico 
Diet: plant-eater (herbivore)