This mixture of pozzolana and lime was then added to an aggregate. 人们把火山灰与石灰的混合物加到集料中。
Since no other volcano lava or pozzolana are found nearby, so we may exclude the possibility that ringed mountains are volcano craters. 而由于相关地带没有发现火山熔岩或火山灰分布，可以排除环形山是火山口的可能。
