Nodosaurus

Nodosaurus (meaning "knobbed lizard") was a large, armored, quadrupedal (it walked on four legs), tank-like dinosaur. It lived in the first part of the Upper Cretaceous about 113–98 million years ago. Three very incomplete "Nodosaurus" fossils have been found in Wyoming and Kansas; no skulls have been found yet. It was named by paleontologist Othniel C. Marsh in 1889.
"Nodosaurus" was about 13 to 20 ft (4-6 m) long. It was an ornithischian (bird-hipped) dinosaur with bony dermal plates covering the top of its body. It had four short legs, five-toed feet, a short neck, and a long, clubless tail. The nodosaurids had no tail club; it is not known how they defended themselves.