Other mistake: When we see the county sheriff's station wagon pull into the cafe parking lot, it has a California license plate instead of an Oregon "state vehicle" plate.
Continuity mistake: The senator is tossed out of the boat and consumed (with the exception of his head) by the monster, and yet the boat is full of blood.
Plot hole: Despite no one actually seeing the landing site of the meteorite, the sheriff takes his boat and the divers to the exact location of the rock. They go down and immediately find it.
Factual error: As the divers surface, they inform the sheriff that the meteor, despite having landed in a lake the night before, is so hot that it may take weeks to cool off.