>> As for the fertile region- A greater proportion of the monuments in the above poll would be
>> built in a 'fertile region' ...

I was talking about this factoid just the other day. No one is going to impress their gods by building a temple to them on 'the shitty piece of land in the corner'. Building the temple must involve sacrifice, not only of labour and time, but also of good land.

If the temple is for the ancestors' afterlife then you give them good land to live on, otherwise they'll leave.

A big chunk of the west of Ireland is limestone and so many monuments are built from it.