Show I I j i i I i I s i I I t. t 1 I Singing Mud lud Rivers Alter Andes Skyline One of the most Interesting features of the An Andes es the great gleat backbone of cor cordilleras covering ering the northern part of South America sa says s 's Nature Magazine Maga rivers ers of mud zInc zine Is 18 its singing 1 During During certain seasons of the lie year rain falls fails In torrents converting the foothills of the mountains into actual streams of flowing gumbo find and so rapIdly rapidly rap rap- Idly Is this erosion occurring occUlTing the whole outline of a chain of mountains may become unrecognizable in n the course cOUlse of a year ear The higher cordilleras cor with altitudes altitudes alti alti- tudes of to l feet are ale being being be be- ing washed down at fit the lie rate of live five feet or more more a year ear and It Is belle believed 1 that In a n few centuries the Andes willbe will willbe be leveled and formed Into vast plateaus like lIle the lie hinterland of Pata Pata- gonia The mountains moun ore are composed for forthe forthe forthe the most part of ot glacial moraine a U mixture of powdered pow rock and an 1 clay cloy The winter rains carry this alluvial lal material down the alle valleys s 's In a semi semi- semi semi-I liquid state an and form vast plains It gurgles with a n musical sound like e I poured molasses 1 |