128 THOMSON— PROGRESS OF THE ISTHMIAN CANAL. 



[April 19 



The dam itself is to be in reality a great earth bank spanning 

 a distance of about 7,700 feet between the hills, and it will be not 

 less than 2,600 feet wide at its base, tapering to a crest of about 

 100 feet wide and this crest will be considerably over 100 feet above 

 sea level, with a great concrete spillway near its center. At the 

 site of the dam, careful rock soundings have been made, a work 

 which was still going on, and samples brought up from various 

 depths were examined. These show that at distances from the 

 present surface of the ground, varying from a few inches to 200 

 feet or more, a solid compact rock, called indurated clay, some- 

 times including fossil marine shells, exist; slaty gray in color. The 

 engineers seem so far to be satisfied with the nature of the founda- 

 tion on which the great dam will rest, in view of its great width 

 at the base, which is regarded as giving ample stability. 



The material required for the construction of the dam will be 

 largely that brought down from the heavy cutting at Obispo and 

 Culebra, though at the time of the visit of the writer, none of this 

 was being used at the dam, as the transportation facilities had not 

 been completely arranged. The problem is one of transportation 

 and the conditions will be much improved when the double track- 

 ing of the Panama Railroad is completed. This with the exception 

 of nine miles, had already been done. Besides this, many large 

 modern locomotives and construction cars are soon to be added to 

 the plant, already so extensive. In the meantime, some of the 

 small capacity dumping cars left by the French Company are being 

 used, as are also some of the numerous small French locomotives, 

 found along the line. The parts of some twenty-five or thirty new 

 locomotives were seen on flat cars, awaiting assembly at the shops 

 in the zone. 



Leaving Gatun, the railroad follows up the Chagres River at 

 a varying distance therefrom, through a country which is at first 

 but slightly hilly, but which becomes more and more rolling. It 

 is for the most part covered with a thick growth of tropical jungle, 

 with some cleared spaces. Here and there along the route are small 

 groups of huts or shacks inhabited by negroes ; remains of a mode 

 of life which will gradually be eliminated from the zone. . Often the 

 views from the train are most picturesque, as river vistas and 



