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190 REMARKS ON DESERTS. 
signating the vast levels of these different regions 
by the nature of the plants which they produce, it 
seems proper to distinguish them into deserts, and 
steppes or savannahs, by which terms would be 
meant plains destitute of vegetation, or covered with 
grasses or small dicotyledonous plants. The savan- 
nahs of North America have been designated by the 
name of prairies or meadows; but the phrase is 
not very applicable to pastures which are often dry. 
The Llanos and Pampas of South America are real 
steppes, displaying a beautiful verdure in the rainy 
season, but during great droughts assuming the as- 
pect of a desert. The grass is then reduced to pow- 
der, the ground cracks, and the alligators and ser- 
pents bury themselves in the mud, where they re- 
main in a state of lethargy till they are roused by the 
showers of spring. On the borders of rivulets, how- 
ever, and around the little pools of stagnant water, 
thickets of the Mauritia palm preserve a brilliant © 
verdure, even during the driest part of the year. 
The principal characteristic of the savannahs of 
South America is the entire want of hills. In a 
space extending to 387 square miles, there is not 
a single eminence a foot high. These plains, how- 
ever, present two kinds of inequalities: the dan- 
cos, consisting of broken strata of sandstone or 
limestone, which stand four or five feet above the 
surface ; and the mesas, composed of small flats 
or convex mounds, rising gradually to the height 
of a few yards. The uniform aspect of these flats, 
the extreme rarity of inhabitants, the fatigue of 
travelling under a burning sky amid clouds. of 
dust, the continual recession of the horizon, and 
the successive appearance of solitary palms, make 
