The presence of a layer composed of a compressed calcium based salt suggests earth that eventually became covered by ocean. Calcium deposits make for fantastic

The presence of a layer composed of a compressed calcium based salt suggests earth that eventually became covered by ocean. Calcium deposits make for fantastic preservatives. See caliche and Llano Estecado as examples. * https://en.m.wikipedia.org/wiki/Caliche https://en.m.wikipedia.org/wiki/Caliche * https://en.m.wikipedia.org/wiki/Llano_Estacado https://en.m.wikipedia.org/wiki/Llano_Estacado