The Age of Reptiles (1960)

The Age of Reptiles (1960) tt2041494

The story is about the Mesozoic Era, and the creatures that lived in that time, which include the Triassic, Jurassic and Cretaceous periods. The story follows the lives of the dinosaurs and other Mesozoic creatures, how they ate, battle and engage in other activities. The film has a volcano erupting, killing animals including a Tyrannosaurus. The film then moves to present time earth, postulating what may happen should dinosaurs were still alive; by showing a monstrous , fire-breathing Spinosaurus on the attack; and how it would be destroyed by an a grenade. (IMDB) 

Film by Donald F. Glut