218 



of the serra of Erere, but I have been unable to determine from 

 stratigraphical evidence the rehitive age of the beds of the moun- 

 tains and plains. There can be no doubt that the serra of Erere is 

 older than the true table-topped hills, and the question of its glacial 

 origin needs no further discussion. 



In the sandstone of the serra are occasional veins, partly com- 

 posed of iron oxide. The original vein-rock appears to have been 

 traversed by a perfect network of delicate veinlets of hematite, 

 forming interlaciug laminae often not more than one or two mil- 

 limetres in thickness, which, on the decomposition and removal of 

 the vein-rock, form masses presenting the appearance of honey- 

 combed wood. In 1870, I made barometrical measurements on the 

 summit of Erere, which gave me the height as 970 feet. Since 

 the observations were taken, I have noticed that a point to the west- 

 ward of those I had chosen appears considerably higher, so that 

 the serra is not far from 1,000 feet in height. 



The vegetation of the serra resembles that of the high, sandy 

 campos of the vicinity, and is very scanty. The sandy tracts are 

 sparsely sown with tufts of long, coarse grass. Trees are as usual 

 very small, rough-barked, gnarly-branched, stunted and scorched by 

 campos fires. Oajii trees grow all over the serra, and the Adsitor will 

 always gratefully remember their thirst-assuagiug, acid fruit. The 

 cajueiros of the serra are all very small, and the fruit is dwarfed 

 and rather sour. On the sandy campos the tree is everywhere met 

 with, and the fruit is sometimes very large and delicious. I have 

 never seen a caju tree on the Devonian plain. It is a true campos 

 species, and, as elsewhere in Brazil, it appears to be confined to dry, 

 sandy soils. It flourishes also on the campos in the vicinity of 

 Santarem, where, as well as at Monte-Alegre, a very delicious wine 

 is made from its juice, some of the brands being not inferior to 

 good grape wine. The manufacture of this beverage was known to 

 the old Tupis, who called the liquor ahayii Icauim. The fruit has 

 an extended reputation in Brazil for its anti-syphilitic properties, 

 and it is supposed that the wine also possesses medicinal virtues. 

 Two palms are common on the serra, the Sacuri and Jatd. The 

 former appears to be allied to the Curua, but the leaves are much 

 more stiff and erect. It is rarely seen elsewhere in the vicinity. 

 The Jata grows to a height of about fifteen feet, and is a very con- 



