562 



where the plains of the Amazon terminate. 

 The vast gulph which they seem to form in 

 the upper part of the basin of the Rio Branco, 

 and the windings of the southern slope of the 

 Sierra Parime, have been discussed above *. 

 The limits of the plains of the Amazon are 

 still more unknown towards the south than 

 towards the north. The mountains that ex- 

 ceed 400 toises do not appear to extend in 

 Brazil on the north of the parallel of 14° to 

 15° of south latitude, and west of the meri- 

 dian of 52° ; but it is not known how far the 

 mountainous country is prolonged, if we may 

 call by that name a territory bristled with 

 hills of one hundred or two hundred toises 

 high. Between the Rio das Vertentes and the 

 Rio de Tres Barras (tributary streams of the 

 Araguay and the Topayos), several ridges of 

 the Mounts Parecis run towards the north. 

 On the right bank of the Topayos, a series of 

 monticules advance (according to manuscript 

 maps recently framed at the hydrographic 

 Depot of Rio Janeiro) as far as the parallel of 

 5° south latitude, to the fall (cachoeira) of 

 Maracana ; while further west, in the Rio 

 Madeira, of which the course is nearly pa- 

 rallel with that of the Topayos, the rapids 

 and cataracts (of which seventeen are rec- 



* Vol. vi, p. 520, &c. 



