>I ski regularly and never use sunblock and haven't noticed much sunblock used by others here in Europe. 

Maybe it's just a phenomenon is the U.S. 

>As far as palaeos are concerned, they must have had regular access to vitamin D, not just those near the >coast, given the vitamin D-content of organ-meats(which palaeos routinely ate).

I don't doubt that there was some access no matter where you go. But, given the fact that we somehow possess the ability to synthesize vitamin D from sun exposure would suggest that it wasn't always available in the quantities required. Either that or it's an ability left over from a time when (organ) meat was not a primary food source.