Table 10. Geologic faults in the vicinity of the Upper Paraguay river.1    Name Formation(s) Location Description Falha da Penha2 Urucum From Serra do Amolar to Ilha de Ínsua On the right bank of Upper Paraguay river, from Fazenda da Penha(north of Amolar) to Ilha de Ínsua (north of Lagoa Gaíba); partly buried near Ilha de Ínsua by sediments of Pantanal sandstones of the Urucum formation: 60km long; arkosic sandstones of the Urucum formaion. Falha da Lagoa 2 Urucum, Bocaína From Serra do Amolar to Lagoa Gaíba On the right bank of Upper Paraguay river, in a direction parallel to Falha da Penha, west of Serra do Amolar and Ilha de Ínsua; partly covered by waters of Lagoa Gaíba; may prolong to southeast reaching Morraria de Novos Dourados; 55 km long; arkosic sandstones and calcareous dolomites of the Urucum and Bocaína Formations, respectively.     Falhas do Urucum 3 Urucum, Santa Cruz Along the valley of Córrego Band'Alta Between Morro do Urucum and Morraria do Rabichão; mostly buried by sediments of Pantanal formation. 1 Source: Projeto RADAMBRASIL (1982a&b), Volume 27. 2 Falha means fault, in Portuguese. 3 System of faults, the best known of which is that along the valley of Córrego Band'Alta.