@PaulHammond51
Would a day/night temperature difference of ~100° stress them thermally so much to make them crack? This one appears to me as if it was still hot, semi-melted, when it hit the ground, and also seems to show a direction.

I think a theory about these rocks should explain why there are so many here and not elsewhere around, how they got here apparently on top of the lower sedimentary layers, why they are mostly rounded, what they are made of, etc.

We're in for a fascinating story!