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MINNESOTA BOTANICAL STUDIES 



fied by the development of blow-outs since the dune sand has become 

 more or less perfectly stabilized by invading vegetation. Commonly 

 such hills are more or less united into irregular ranges or ridges 

 with numerous saddles and summits and short lateral spurs. 



The depressions between the individual hills of a given range or 

 between the hills of contiguous ranges, vary from narrow bowl- 

 shaped basins or "pockets" a hundred yards in diameter to valleys 

 or meadows with relativelv flat floors often more than a mile wide 



Fig. 2. Topographic features. A square mile among the "choppy hills." 

 Contour interval 20 feet. (Somewhat idealized.) 



and sometimes several miles in length. The ranges of hills with the 

 alternating valleys and meadows are as a rule about parallel and 

 trend in a general, more or less irregular, northwest and southeast 

 direction. Such conditions as these are very common especially in 

 the northern portion of the region. I am fully aware, however, that 

 in certain other portions (as in Garden County) this typical valley 

 and range trend is not so clear or constant, and there are here very 

 well-developed valleys which take a different course. Single valleys 



