100 Million BC

It is very much possible that the creators of the movie may have wanted more character development in the marines. Evidence of this is seen in the deleted scene of showing what the marines did the night before the time jump, such as Burke talking in his phone seemingly about family issues by the way he makes stressful gestures with his hands, while Jones and Manriquez play a game of cards ending with Jones saying a vulgar remark about Manriquez's mother. Since the movie was partially rushed due to a deadline, most of the marines ended up with little to no character development and are often cited as the most bland characters in the movie, with Reno and the old research team being the only ones with character. Despite all this, they are some of the most important characters in the first half of the movie.

When the rescue team finds the survivors they are dressed in "stone age" gear, including quite a lot of fur hides. Which would have been difficult considering the lack of furry animals larger than very small mice during that era.

References Gilda (1946)