TRANSACTIONS OF THE SECTIONS. 149 



Pastassa, and present great obstacles to the traveller, being unfordable and liable to 

 sudden rises, when they become wholly impassable torrents of enormous volume. 

 The principal of these is the Topo. This much-dreaded stream forms the chief 

 obstacle to communication between Ecuador and the countries to the eastward. 

 The rise of its waters is sometimes so sudden that small parties of traders, with 

 their train of Indian porters, have been separated whilst crossing it, and sometimes 

 imprisoned between it and the next torrent, running parallel, for two or three weeks 

 without the possibility of effecting an exit either way. It rushes, or rather springs, 

 down its bed at a frightful pace ; and as this is filled with unevenly dispersed 

 boulders piled up between high rocky banks, the waters leap up to a great height, 

 filling the air with spray. It was in this condition as Mr. Simson and his party 

 approached it after a wet and stormy day's march. The spray and even the heads 

 of the crests thrown up from the boulders washed over the rude suspension bridge 

 by which the steram is usually crossed. These sudden floods are caused by the 

 sudden melting of the snow in huge rifts on the eastern flanks of the Ecuadorian 

 Andes. The waters fell on this occasion as suddenly as they rose, and the author 

 continued his march down the left bank of the Pastassa until he reached a small 

 village of the Jivaro tribe of Indians, near the little river Pintuc. Here he com- 

 menced his westerly march across the country to the banks of the Napo. The 

 path lay through the same continuous forest which clothes the whole of Eastern 

 Ecuador, but the steep mountains had here subsided into lower elevations. A 

 peculiar feature of the country was the constant recurrence of long ridges with 

 narrow summits, called by the Spaniards cuchillas (knives). These run generally 

 for ten or fifteen miles, and have an elevation from their base sometimes as 

 great as 500 feet. On one side they are almost perpendicular, and on the other 

 they descend at a sharp angle. They are composed wholly of loose vegetable 

 earth and loam, and are held together by the entangled roots and vegetation 

 with which they are covered. The explanation of these curious ridges, which 

 occur often between parallel rivers, is not far to seek, in a country where the de- 

 nuding forces of copious precipitation and flooding waters are displayed on so mag- 

 nificent a scale. They are simply those portions or " cores " of laud which have 

 resisted to the present time those denuding agencies that have been for ages at 

 work grinding down the surfaces of the Eastern Andes and spreading the materials 

 over the plains at their feet. The coarser portions of the detritus are spread over 

 the region immediately contiguous, forming the gradually sloping country through 

 which the Nago and Pastassa flow, which has been worn into valleys, hills, and 

 cuchillas ; and the finer silt has been carried by the streams down to the Amazons 

 and thence to the Atlantic. The route followed by Mr. Simson crossed the Bobo- 

 naza to the little settlement of Canelos, and thence to Curarai. The last-mentioned 

 stream, scarcely known to geographers, has its sources on the outermost slopes of 

 Llanganati, and after receiving the waters of the Villano, Nushinu, Supinu, Nuganu, 

 Pundinu, and others, empties itself into the Napo on the right bank. The party 

 reached the Napo, opposite Aguano, after eighteen days actual walking from Banos. 

 The Napo at Aguano was found to be a noble river, broader than the Thames at 

 London Bridge, even when not flooded. At this point the distance is 3100 miles 

 from the ocean, and no obstacle to navigation exists the whole way. 



On tJie Ascent of the River Putumayo, South America. 

 By Alfred Simson. 



On his journey down the Amazons from the Napo, Mr. Simson seized an oppor- 

 tunity which offered to take the command ef a small steamer lent by the Brazilian 

 Government for the purpose of pioneering the way up the little-known river Putu- 

 mayo, an affluent of the Upper Amazons on the left bank. The Expedition origi- 

 nated with some energetic merchants of Popayan, in New Granada, who had entered 

 into an agreement with the Brazilian Government with the object of opening up 

 this stream to steam navigation and trade, in the conviction that it could be made 

 an easy outlet for the products of the rich province of Pasto in New Granada sur- 

 rounding its headwaters. One of these enterprising men had previously descended 



