sentences:  The calcium in limestone makes it water-soluble and easily eroded, yet limestone builds up over eons, a stratum at a time, out of organic matter, recalling the stratified history of Mediterranean civilisation.Interpreting the metaphor of ground in poetry, the critic Rainer Emig writes, "The ground [is] a perfect symbol of cultural, ethnic, and national identity, a significatory confluence of the historical and the mythical, individual and collective.