I have three of Immanuel Velikovsky's books. Twenty plus years since I read them and they are heavyish.

His basic theory; one of them; was that a major planet passed close to the Earth and caused the Earth to reverse on it's axis, i.e. The North Pole became the South Pole and vice versa.

There are many proofs that this might have indeed happened.

One example which comes to mind concerns the whelk, where the spiral of the shell in all whelks run in the same direction subject to living in either the Southern or Northern Hemispheres where they run in opposing directions.

Prior to The Event, the spirals all ran in the opposite direction.

In other words, the whelks have reversed the direction of their spiral, whether they live in the Northern or Southern Hemisphire.

Memory!