Character mistake: In a conference with Crockett and Bowie, Travis states that Fannin in Goliad is preparing to relieve the Alamo and will be ready to "march south by the end of the week." Goliad is 90 miles south of San Antonio. To relieve the Alamo, Fannin would need to march north.
Character mistake: At the end, Professor Challenger misidentifies the dinosaur in the boiling water as a T-Rex. Its arms are too long, and it sports horns. It is much more likely a carnotaur. This area being a forte of his, I doubt Professor Challenger would make this mistake.