B8 
Boiayzical Reminiscences, 
brown ironstone fragments, which now and then alter- 
nate with sharp fragments of quarts and granite. Small 
forests, which I have called oases, sometimes to the extent of 
miles, otherwise more limited, mostly of a circular form, 
rise from the savanna like islands out of the ocean. 
They mostly consist of the noble forest trees, but which 
seldom reach the luxuriance and height of the trees in the 
forest. The soil of these oases of course entirely differs from 
that of the savanna. It consists chiefly of a rich humus or 
marshy land, often also of heavy clay mixed with sand and 
Tegetable matter. In such oases as have marshy ground, or 
contain sources of rivers and rivulets, the predominating vegeta- 
tion are palms, ferns, and Scitamineae, 
A border of vegetation lOO to 200 feet wide, sometimes 
more or less luxuriant, but very dense growing trees and 
shrubs, follow the rivers of the savanna. The stratum of humus 
covering the savanna occasions also an essential alteration of 
the vegetation. 
The grasses are rough and squarrose, and con sist mostly of 
Cyperacece, interspersed with numbers of prickly herbaceous 
or woody plants of the order of Malpighiaceae, Leguminosae, 
Mubiaceaey Myrtaceae, Malvaceae, Convolmilaceae, Menisperma- 
rueae, Apocynaceae, etc. The growth of the isolated trees, 
especially on the elevated ground, as Curatella americana, 
Bowdichia major, is stunted. 
In marshy ground the savanna is occupied by the Mauritia 
palm, sometimes single, sometimes forming copses. 
In this region occurs only on 3 rainy season, commencing 
generally during April, and ending in July or the beginning 
of August. The quantity of rain falling is about eighty to 
ninety inches. 
During the dry months an equable climate exists. The 
horizon is generally clear, often for months without any change, 
without rain, and with a constant easterly wind. The medium 
temperature fluctuates then between 80^ to 86'^ Fahr. The 
humidity required for vegetation is kept up by heavy dews, 
which appear not only in the region of the forest, but also in 
the savanna, so strong that in the morning the vegetation is 
saturated as if heavy rain had fallen. 
Most of the small creeks and rivulets become dry during 
the dry season — vegetation ceases, but only a few trees in the 
voases and on the banks of the rivers lose their foliage. These 
vmostly belong to the Bignoniaceae, Tecoma Jacaranda, and 
Erythroxyleae as Erythroxylon. 
