Jon Ellison wrote:

> If the romans were adept at granite carving why did they feel
> the need to incorporate replica brick and plaster columns
> alongside visually identical granite columns within the same
> structure. Why not all granite?
> Why were there not enough available roman carved granite
> columns to complete the job.?

Problems with the supply routes strikes me as the most likely cause.
Supply columns coming under attack in Egypt.
Ships carrying the columns sinking in the Mediterranean.
Cost of shipping became too high.
Sickness amongst the quarry workers.
A political situation.
Why, there's a host of possible reasons - and all of them perfectly mundane.

MJT