Table 5. Stratigraphic units in the vicinity of the Upper Paraguay river.1 Era Period Epoch Group Formations Precambrian Upper _ Alto Paraguay Moenda Araras Raizama Sepotuba - Corumbá Puga Cerradinho Bocaína Tamengo - Jacadigo Urucum Santa Cruz Paleozoic Silurian - - Coimbra Mesozoic Triassic - - Alkaline Fecho dos Morros Cenozoic Quaternary Pleistocene - Xaraiés - Pantanal Holocene - Pantanal 1 Source:  Projeto RADAMBRASIL (1982a&b).