1902.] HATCHER — OLIGOCENE AND MIOCENE DEPOSITS. 129 



fringe of forest on the river bank. The river at the flood season 

 covers these lands almost entirely. It must be remembered that the 

 upper Paraguay rises about thirty feet annually. 



" All the flatlands above the Fecho dos Morros to Villa Maria — 

 over four hundred miles in a direct line — are subject to river floods, 

 and these are deepest toward the north. The width of the flood- 

 plain at the mouth of the Sao Louren^o can hardly be less than one 

 hundred and fifty miles from the rocky lands on the east to the base 

 of the Serra dos Dourados. The whole region is a labyrinth of 

 lakes, ponds, swamps, channels and islands in a grassy plain, the 

 only forest being near the river. I had a fine view of this plain 

 from the foothills of the Dourados ; even the flood-plains of the 

 Amazon cannot compare with it in its tangle of land, water and 

 marshes. Only the most experienced canoeman can thread his way 

 through it ; generally travelers trust to the Guato Indians, who are 

 the only inhabitants of the region and literally live in canoes. 

 Castelnau was lost there and only found the river channel with 

 great difficulty. We were lost or partly lost for a few hours, though 

 we had three experienced hands. 



'^ This is the region called Lake Xaraes, or Charaes, by the old 

 explorers ; Brazilians called it the Pantanaes, literally The Marshes. 

 Even at low water at least one-fourth of it is flooded : when the 

 river is at its highest the whole plain is a vast lake covered with 

 floating grass and weeds ; it is possible to pass almost straight 

 across it in a canoe, though with great difficulty. Only a few 

 islands remain here and there ; jaguars, deer and ether animals 

 take refuge on them, and they are favorite hunting grounds of 

 the Guatos. 



'^ The rainy season is from October to April, the heaviest rains 

 being toward the last; the small rivers from the highlands are 

 flooded in March and April, and pour their waters over the flood- 

 plain. But it takes a long time for these waters to spread over 

 the plain. Consequently the highest waters on the plain are 

 in July and August. Then they gradually drain away through 

 the Fecho dos Morros, and the lowest waters are found about 

 February. 



"The eastern and northern sides of the flood-plains are bordered 

 by low rocky lands which extend for a few miles inland : then they 

 rise precipitously 1500 or 1800 feet to the Brazilian plateau. The 



PROC. AMER. PHILOS. 80C. XLI. 169. I. PRINTED JUNE 10, 1903 



