TOPOGRAPHY OF CENTRAL WYOMING 



every hand and are the most characteristic thing to be seen in 

 the region. They are usually oval in form; frequently they 

 have no outlet. They may or may not be occupied by w^ater; 

 in the former case there is usually a v^ide belt of alkali surround- 

 ing the pond. These basins owe their origin to a number of 

 causes. Usually the basins occur in drainage channels and are 

 formed by the ponding of the streams by the debris carried in 

 by tributaries. 



As is often the case, the tributaries work back along the 

 strike of the soft rocks and thus are enabled to carry down great 

 quantities of detritus, which the parent stream is unable to 

 handle. Under such circumstances a basin will result sooner 

 or later. In a few localities there was evidence of basins being 

 formed by tectonic agencies. The best example of this was 

 a basin in the neighborhood of Cooper's Creek, which had 

 been formed by the uplift of a small fold across the stream. 



In the neighborhood of Harper, there were a few basins 

 that had been formed by wind action; indeed, the process of 

 construction could be seen going on in the strong wind which 

 swept the region a good share of the time. A characteristic 

 of such basins is that the coarse gravel is left behind, while the 

 fine debris, such as sand and fine pebbles, is swept away; 

 hence the bottoms of such basins are distinguished by the coarse 

 character of the gravel. In a few instances, solution basins 

 were observed; these were the round or oval-shaped basins 

 which occurred in limestone regions; they had no apparent 

 outlet. Such basins are not numerous, and they are not a 

 special feature of the region. No basins were observed that 

 could be attributed to glacial action; local glaciers have 

 doubtless occurred in the region, but they have left no well- 

 defined basins behind them as an evidence of their occupation. 



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