please help finding name of anime.

[angelok]

Hello and greetings.
I'm Angelok.

I'm posting here to hopefully find an ID on an anime based on very little info.
Its a long shot, but.. never know !

Here's the info:

"It had the length of a movie, kinda like Akira,
and it was about some kid, a girl and her younger brother who got
transported back in time and ended up in the prehistoric era."

Presumable its late 70s/early 80s.
Any ideas ?

[webmaster]

Is it Doraemon: Nobita's Dinosaur from 1980?