I 72 



THE POPULAR SCIENCE MONTHLY 



Photo, W. H. Rau, Philadelphia. 

 Railway from Bermudez Lake to Whakf at Guanaco. 



The general surface of the lake is very irregular and hard. There 

 are many very narrow and irregular channels or depressions from a few 

 inches to four feet deep, filled with water, and, not being easily distin- 

 guished, one often falls into them. At the foot of the growth of grass 

 and shrubs are ridges of pitch mingled with soil and decayed vegetation, 

 which have been plainly coked and hardened by fires originating in the 

 surface growth. When this hardened material which forms only a crust 

 is removed, asphalt of a kind suitable for paving is found. The crust 

 is from a foot and a half to two feet in depth and very firm, while the 

 asphalt underneath would not begin to sustain the weight which that 

 of the Trinidad pitch lake does easily. There are breaks in the crust 

 here and there through which soft pitch exudes, as has been described. 



It appears, therefore, that the Bermudez deposit owes its existence 

 to the exudation of a large quantity of soft maltha, which is still going 

 on and which has spread over a great area; that this has hardened 

 spontaneously in the sun, and has also, by the action of fire, been con- 

 verted over almost the entire surface into a cokey crust of some depth, 

 beneath which the best material lies, and that here and there are scattered 

 masses of glance pitch produced in a similar way from the less violent 

 action of heat. There is no evidence of a general movement and 

 mingling of the mass of this deposit in any way that would produce a 

 uniformity of composition, as seen in the Trinidad pitch lake, although 

 there is a certain amount of gas evolved at the soft spots where maltha 



