Corrected entry: After the three astronauts woke up, they notice that they have large beards due to the time they spend in suspended animation. However, their hair hasn't grown an inch.
Corrected entry: In the final scene, Charlton Heston and the girl are heading south and the ocean is on their right, (and the lake they crashed in is out west), so we know they are on the west coast. So how does the Statue of Liberty wash up over there? Maybe the Apes kept the Panama Canal open.
Correction: You're assuming they are on the North American continent as it exists today. But they could be be on land that has risen from the Atlantic and are looking west over the ocean that used to be North America, the changes having been wrought by the same disasters that buried the Statue of Liberty in sand.
Corrected entry: An essential plot device is that the talking human doll proves humans were productive and creative before the ascent and takeover of the apes. This is absurd. We are shown repeatedly that the apes' entire society is based heavily upon the previous human one - this is a sneaky buildup to the end scene when we find out exactly why that is! So, in human society we have talking mice, ducks, rabbits, pigs, cats, dogs, snakes, elephants, fish, crabs: name the species, we have given them the ability to speak, walk upright, drive cars, in fact to adopt every human characteristic there is. Surely the logical assumption upon finding the talking human doll is that an ape toymaker created a talking human for the same reason humans created talking apes?
Correction: This is a question, not a mistake. The talking human doll is not a plot device; just something that Taylor uses to help prove his point. Dr. Zaius already knows that humans once ruled the planet; he was just stuck for an explaination of why the doll talked when he first saw it. Given time he would have postulated that apes created it, but was interrupted by the attack on the cave.
Corrected entry: The astronauts should had immediately realized they were back on Earth, at the beginning of the movie, if they had only gazed at the Moon or constellations in the night time sky (even if it was the year 3978). Naturally that observation would have made that a different movie.
Correction: A comment is made very early in the movie about the thunder and lightning with no rain and how there is a strange luminescence but no moon, which would make the stars invisible too. The climate and night sky may have been drastically changed by whatever has happened in the years since they have been traveling.
Correction: Facial hair (beards and moustaches) grow much faster than head hair. The three astronauts were probably shaved almost to the scalp before entering suspended animation.
Grumpy Scot