280 PLATEAU OF CAXAMARCA. 



for leaves at a distance, proved to be thickly crowded brae- 

 teas. The appearance was altogether different, in the 

 purity and freshness of the colour, from the autumnal 

 tints which, in many of our forest trees, adorn the woods 

 of the temperate zone at the season of the fall of the leaf. 

 A single species of the South African family of Proteacese, 

 Hhopala ferruginea, descends here from the cold heights 

 of the Paramo de Yamoca to the hot plain of Chamaya. 

 We often found here the Porlieria hygrometrica (belonging 

 to the Zygophyllese), which, by the closing of the leaflets of 

 its finely pinnated foliage, foretels an impending change of 

 weather, and especially the approach of rain, much better 

 than any of the Mimosacea3. It very rarely deceived us. 



We found at Chamaya rafts (balsas) in readiness to convey 

 us to Tomependa, which we desired to visit for the purpose 

 of determining the difference of longitude between Quito 

 and the mouth of the Chinchipe (a determination of some 

 importance to the geography of South America on account 

 of an old observation of La Condamine). ( 10 ) We slept as 

 usual under the open sky on the sandy shore (Playa de 

 Guayanchi) at the confluence of the Rio de Chamaya with 

 the Amazons. The next day we embarked on the latter 

 river, and descended it to the Cataracts and Narrows (Pongo 

 in the Quichua language, from puncu, door or gate) of 

 Renterna, where rocks of coarse-grained sandstone (conglo- 

 merate) rise like towers, and form a rocky dam across the 

 river. I measured a base line on the flat and sandy shore, 

 and found that at Tomependa the afterwards mighty Biver of 

 the Amazons is only a little above 1386 English feet across. 

 In the celebrated River Narrow or Pongo of Manseritche, 



