When young Jack enters the neighbor's house to snoop, there is a brief glimpse of a tuned wind chime which is heard sounding. Tuned wind chimes didn't exist in the 1950s; there were only the un-tuned, jangly type (and very few of those in middle-class Texas homes).
During the prehistoric sequence, explicitly shown to be prior to the event which wiped out dinosaurs, we see a shot of sharks. Then we see a large Manta Ray. The Manta Ray evolved from shark-like ancestors only as recently as 5 million years ago, much too late to coexist with dinosaurs who lived prior to 65 million years ago.