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Wherever a sandy soil oce-urs uniirotected by vegetation dunes are 

 built up. They are usually roughly stratified, the degree of stratifica- 

 tiou and the thickness of the beds depending upon the force and direction 

 of the wind. The sand grains become much rounded by abrasion, and in 

 many cases become very small. Sand grains are heavier than dust p.'.r- 

 licles and are not raised far above the surface by tlie winds; the larger 

 grains being rolled along on tlie surface. The movement is very similar 

 to that of "frozen" snoW in drifting. 



From Michigan City, Indiana, west for a. distance of about twenty- 

 five miles the lake beach presents a line of sand-dunes, averaging in 

 width from one-third to one-half mile, and in places 150 to 200 feet 

 high. Farther to the west to the State line the beach spreads out into 

 a broad belt of low ridges running parallel and with an extreme width 

 of about two miles. It has been estimated that after deducting the 

 sand deposited by Lake Chicago that at least half a billion cubic yards 

 of material have been added to the surface of Lake and Porter counties 

 alone by the waters of the present lake. The dunes and ridges are 

 most typically developed on a large scale about Michigan City in the 

 great "Hoosier Slide," which has stood as the greatest and most noted 

 of the dunes. During the past few years this dune has had its bulk 

 greatly decreased by the hauling away of the sand by the hundreds of 

 train-loads for various economic purpo.ses. The sand sells for about 

 three dollars a carload. Railroad switches are laid along the sides of 

 the dune and steam shovels scoop out the sand and dump it into the 

 cars. Many cars are also loaded with hand shovels and wheelbarrows. 

 When a cavity is made in the sand the wind soon brings down a new 

 .'■upply from the top and renews the deposit. A sand brick and building 

 block factory located in the southeastern part of the dune finds its sup- 

 I)ly of raw material continually replaced at its shed doors. Practically 

 all the railroads entering Chicago have used this sand in track ballast 

 and elevation. Great trestles have been filled and swamps and marshes 

 along rights of way have been covered with the sand. The dunes and 

 ridges at Dune Park, about twelve miles to the southwest of Michigan 

 City, are very extensive and are also a source of much of the sand shipped 

 out for numerous purposes. In addition to the use mentioned the sand 

 is used for the filling of city lots, building sand, and many manufactured 

 products. 



