424 A YEAR IN BRAZIL. 



very high angle, the softer strata being gradually washed away. 

 Such remarkable forms as the Sugar-loaf, the Pedra da Gavea, 

 the Corcovado, and others near Rio, with the Pedra da Fortaleza 

 near Parabybiina, are instances of the same phenomena ; the views 

 of sublime beauty which these marvellous peaks present, with the 

 luxuriant vegetation which drapes their less abrupt sides and 

 covers the fertile valleys at their base, at once arrest the atten- 

 tion and charm the eye of even the most insouciant of travellers. 



My various visits to the railway in course of construction up 

 the Corcovado afforded some insight into the decomposition of 

 the gneiss. I have mentioned that the railway crosses huge 

 gorges, and then plunges into tremendous cuttings. The latter, 

 sometimes nearly a hundred feet deep, were often entirely through 

 decomposed strata, reduced to a clay which could be scraped 

 with the finger, and in which the lines of stratification, contortion 

 of- strata, anticlinal and synclinal axes, etc., are very distinctly 

 marked; the clay being interspersed with veins of hard quartz, 

 and sometimes masses of grey granite which had to be blasted. 

 The photograph of the Principe do Grao Para Railway to Petro- 

 polis gives an instance of such masses of rock standing out from 

 the decomposed gneiss. These phenomena occur along the 

 whole course of the Estrada de Ferro Dom Pedro II. to Queluz de 

 Minas, and over our line to Pitanguy, being strongly marked at 

 the divides. To the engineer these features are inconvenient. 

 The masses of hard rock necessitate very sharp curves in following 

 the course of the rivers near the watershed, especially past the 

 frequent cachoeiras (cataracts' or waterfalls), when the river may 

 suddenly, after passing along a flat valley half a mile in width, 

 dash through a gorge twenty to fifty feet wide, with vertical sides. 

 -Then, again, the argillaceous schists are very treacherous, both in 

 cuttings and banks. In the former, the formation width has to be 

 considerably wider than the line, to allow for the large amount of 

 clay eroded from, the sides during the rains, and this is so serious 

 occasionally as to stop the traffic. In forming the embankment, 

 great care has to be exercised in the stuff used, large side-excava- 

 tions being often imperative, or even recourse to a neighbouring 

 slope to obtain good material; but after every precaution has 

 been taken, the banks may subside or slide away during the rains. 



