Both, plus absence of seat belts. Rear facing with no head support is a good way to snap your neck if you are wearing a belt, but because we weren’t, we’d probably be flying forward to the windshield.

https://www.automobile-catalog.com/img/pictonorzw/plymouth/1...

Looking at that picture, I see belts, but I do not recall those belts and suspect they were deeply wedged into the seat and forgotten about.