SHORTER ARTICLES AND DISCUSSION 



ON THE FAUNA OF GREAT SALT LAKE 



In a recent number of the American Naturalist^ appeared a 

 paper entitled ''Notes on the Fauna of Great Salt Lake," by Dr. 

 Chas, T. Vorhies. From observations made by the present 

 writer in the region at the mouth of Bear River, Utah, during 

 the summer and fall months from 1914 to 1916 inclusive, infor- 

 mation is available that supplements in part the data given by 

 Dr. Vorhies, 



Bear River, the largest of the three main tributaries of Great 

 Salt Lake, breaks up into a series of channels at its mouth and 

 forms a great delta at the northern end of Bear River Bay. Im- 

 mediately below the mouth of the river the waters of the bay are 

 freshened by the incoming river water. Conditions here vary 

 greatly however from day to day, and at present heavy salt water 

 frequently comes up as far as Slaughter Island at the lower part 

 of the marsh area in the river delta. Below this point the sur- 

 face water coming from the river may be fresh while at a depth 

 of a few inches a stratum of brine may overlie the mud. On 

 calm days this overlapping proceeds for long distances. The 

 prevailing summer winds liowever are from the south and south- 

 west and these drive tlio salt water in toward the marsh nearly 

 every afternoon. 



as a dam to separate Bear River Bay from the main lake (cf. 

 Vorhies, p. 494). For a considerable distance this causeway is 

 made up of trestle work allowing free interchange of water from 

 either side. Although tests of the density of the water were not 

 made, the writer is certain that the difference in content of salts 

 between the water on the north and south sides of the cut-off is 

 slight while water sufficiently saline to enable the life characteris- 

 tic of the Lake to flourish is found at least twelve miles above 

 the cut-off and within four or five miles of the point at which 

 the main channel of Bear River opens into what is known as 

 South Bay. 

 1 Vol. LI, No. 608, August, 1917, pp. 494-499. 



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