i6 JUNGLE ISLAND 



tropical river to help them flood the Chagres 

 valley and make Gatun Lake. At Gatun they 

 built a wide, gently rolling hill that is so broad 

 and grassy that it does not look like a dam at all. 

 This stands.straight across the path of the Chagres 

 River. When it was finished, it caught and held 

 back the river waters. The water rose higher 

 and higher as the heavy summer rains fell, until 

 it reached at last the top of the locks and the 

 spillway (Fig. 4) . When it stood eighty -five feet 

 above sea level, the extra water was allowed to 

 run over the spillway and off down the old river 

 bed to the Atlantic. 



While the waters of the new lake were rising, 

 there was a long time of moving among the 

 mysterious animals that lived in the great forests 

 of the drowned Chagres valley. The people of 

 the few native villages the lake would cover had 

 been warned in plenty of time and given new land 

 high and dry. Nobody warned the animals. 

 Every day as the water rose they moved back a 

 little higher, and often in the morning they found 

 they had been cut off in the night from old hunt- 

 ing grounds and play places. Most animals can 

 swim, but not many of them like to, especially 

 when there are crocodiles in the water. They 

 preferred to go higher in the hills. Even the 

 sloth, which hates to move at all, had to sling 

 himself from one branch to another as the water 

 rose. 



