Not to confuse the matter. This may not even be relevant however, I was watching one of those Ancient Civilization shows. In this case, it was the Roman Empire. The explained how the Romans engineered aquaducts across long uneven terrain; building combounds and technique to assemble and upright giant columns and facades, etc., They spent a fair amount of time explaining the geology of Italy, the use of Volcanic ash, and other (I wish I could remember) Volcaninc soil, due to it's mineral make up and so on. When I saw it - It sounded like what I have read is "Biscotto di Sorrento" I remember them saying that it was the genius of the Romans along with the good fortune of being in a volcanic area that allowed them to develop these kind of "technologies." I'll see if I can find it but they had a British Historical Geologist duplicate the method of creating the Romans' light but very strong materials - perhaps there are some bread crumbs to follow there? Or is it Pizza crumbs? I'll see what I can find. I watch a lot of History, Nat Geo, etc. It was assuredly on one of those channels.