4 Gardiner G. Htibbard — South America. 



where it is only 150 miles wide. Its total fall from the foot-hills 

 of the Andes to the Atlantic is very slight, not over three or four 

 hundred feet, and probably considerably less. 



The rims of the valley are formed of diorite and sandstone, 

 and are raised only a little above the flood-plain, which is formed 

 of mud and silt, the detritus brought down by the Amazon and 

 its tributaries. The flood-plain is from fifty to one hundred 

 miles wide, gradually narrowing as it approaches the ocean. 

 Through this valley the Amazon cuts its way, separating often 

 into channels which sometimes run parallel to each other for 

 several hundred miles, frequently forming large islands, or 

 expanding into lakes. Similar flood-plains are found on all its 

 larger tributaries. 



Up from the ocean into this valley an immense tidal wave rolls, 

 with a bore, twice a day, forcing back the current of the Amazon 

 500 miles and inundating a portion of the flood-plain. 



In the early autumn the equatorial rise commences in the head- 

 waters of its tributaries, far south of the equator. The rains 

 and melting snow raise the streams, and these the waters of the 

 Amazon. As the sun crosses the equator and moves to the north 

 the rain follows its course, and the branches that have their source 

 in the east and northeast add their flood to the waters of the 

 southerly branches. The flood in the Amazon is thus continued 

 for nearly six months, raising its waters from 30 to 50 feet. The 

 channels are filled, and the flood-plains are overflowed. The whole 

 valley becomes a net-work of navigable waters, with islands and 

 channels and lakes innumerable, forming a great inland sea, which 

 the Brazilians call the Mediterranean of America. The upland, 

 though only a little above the flood-plain, is rarely overflowed. 



The plants and animals of the flood-plain were formerly con- 

 sidered as distinct from those of the upland'as are the plants and 

 animals of Europe from those of America ; but later investiga- 

 tions show that there is but little difference between the species. 



The sea breeze blows up the valley about a thousand miles. 

 Then for 1500 miles the atmosphere is stagnant and sultry ; the 

 climate is that of a permanent vapor bath. The dense foliage 

 forms dark, lofty vaults which the sunlight never penetrates, and 

 over all hangs a perpetual mist. The abundance and beauty of 

 vegetation increases, and the trees which at the mouth of the 

 river blossom only once a year, here bloom and bear fruit all the 

 year round. 



