At 02:29 PM 4/29/2005, you wrote:
>If anyone remembers a specific source for this, such a lesson, a book,
>a TV program or movie

I remember an animated 30 second commercial from the 70's (by Chevron, I
think) that showed a kind of stylized "time-lapse photography" progression
beginning with a four legged dinosaur eating plants and ending with a happy
motorist driving into a gas station and filling up. So apparently at that
time it was a pretty well established bit of folklore. Near as I can figure
from doing a little google research, the blame can probably be laid
squarely on the shoulders of Sinclair Oil Corporation, which started using
a dinosaur as its symbol back in 1930
<http://www.sinclairoil.com/about_sinclair.htm> and sponsored a display at
the '33 World's Fair featuring several dinosaur models. Probably intended
to representative of the TIME oil came from, it was likely misinterpreted
as representative of WHAT oil came from.