- 19 



by closing the entrance of the river completely for vessels 

 of more than 3 feet of draught. This circumstance however 



helps to decrease the dangers arising from the existing 

 shallow places in the river where there is stone. 



This second part embraces an extension of 87 kilometers, 2nd - section. 

 which differs greatly from that described before. Inmedia- From the mouth of 



i r\ l ' l ■ l '" : "' ' ' ,1,a ' e ' 



tely above the mouth of the Kiver Lhialeguaychu begins guaychu to con- 



.. . , . ion del Uru- 



tlie formation of islands which increases when going up guay. 



river and which islands separated by several arms or creeks 

 form in the neighbourhood of «Las Tres Bocas » (the three 

 mouths) a delta with a width of 12 kilometers which is 

 completely flooded when the river is high. 



This circumstance renders navigation in this part easy 

 for the pilots, in consequence of the many landmarks which 

 the banks offer to them. 



Already in this section the great difference in level is 

 observed during great flows of water. The greatest slope 

 observed is 0,0467 meters per kilometer, the mean slope 

 when the river is high is 0,0195 between Fray Bentos and 

 « Banco Grande » and 0,035 meters between the latter loca- 

 lity and Concepcion del Uruguay (Sheet III). 



The mean velocity observed in the bar of «Banco * iran- 

 de » was 0,714 meters and the greatest was 1,16 meters 

 when the level of the river was 2,70 meters. 



In this latter part with the greater slope, are the diffe- 

 rent sand bars situated, which are an obstacle to navigation 

 with vessels of great draught. 



The influence of the tides is felt in the port of Concepcion 

 del Uruguay to a height of 2 meters at the gauge, their 

 mean height, when the river is low, being 62 centimeters. 



From Fray Bentos to the North point of the Zapatero 

 Island there is only one channel for the navigation, and 

 the difficulty in this part consists in avoiding the South 

 part of the Abrigo Island in front of which the «Unzues> 

 port ( also called Abrigo » or « Nandubayzal port ). is 

 situated, which was examined by a commission of the Navy 

 in the year 1882. 



A litte above the Zapatero Island navigation can select 

 from two channels which are called the « Boca Chica » 

 and the « Filomena channel. The first named channel 



