FLCrCTUATIOKS OF DEVILS LAKE. 595 



in cycles of uljout ;i dozen years, during which comparatively scanty 

 average rainfall for several years was followed by unusually abundant 

 rainfall.-' These fluctuations are similar with those just noted in the ram- 

 fall of North Dakota. Besides such short cycles, important secular changes 

 of the mean annual precipitation in this State, occupying considerably 

 longer periods, have caused remarkable changes in the levels of numerous 

 lakes which have no outlets. 



Devils Lake" thus shows evidence of having attained, about the year 

 1830, a level 16 feet higher than its low stage in 1889, reaching at or near 

 the former date to the line that limits the large and dense timber of its 

 bordering groves. Below that line are only smaller and scattered trees, of 

 which Capt. E. E. Heermau informed me that the largest found by him and 

 cut a few years ago had fifty-seven rings of annual growth. Within the 

 twenty-five yeai-s since the building of Fort Totten this lake has fallen 9 or 

 10 feet, and it has fluctuated 4 feet under the influence of the changes in the 

 average annual precipitation of rain and snow during the jnxst dozen yeai's. 



The high stage reached by this lake about sixty years ago appears to 

 have been limited by an avenue of discharge eastward into Stump Lake, 

 which rose at the same time to within about 3 feet of this height. The 

 latter and smaller lake, receiving no large tributary and lying in a basin 

 that nowhere extends many miles from the lake, was prevented by evapo- 

 ration from rising quite so high as Devils Lake, which during years of 

 abundant rains and snows receives a large tributary, the Mauvaise Coulee, 

 di-aining a broad area that stretches 60 miles northwestward to the Turtle 

 Mountain. The outlet from Devils Lake into Stump Lake was nearly due 

 eastward from Jerasalem, situated on Lamoreaux Bay at the most eastern 

 portion of the entire lake shore. With an overflow at this point, Devils 

 Lake may many times have been raised to this beach by the periodic 

 variations in rainfall during the many centuries since the Ice age.^ 



' Charles Whittlesey, " On fluctuations of level in the North American lakes," in Smithsonian Con- 

 tributions to Knowledge, Vol. XII, 1860, pp. 25, with 2 plates. 6. M. Dawson, in Nature, Vol. IX, pp. 

 S04-506, April 30, 1874. Bola Hubbard, in Popular Science Monthly, Vol. XXXII, pp. 373-387, Jan., 

 1888. G. K. Gilbert, in The Forum, Vol. V, pp. 417-428, June, 1888. 



= Sce pp. 169-171, with PI. XVIII. 



3 Compare with Mr. Gilbert's hypothetic explanation of the Stausbury shore-line of Lake Bonne- 

 Tille, U. S. Geol. Survey, Monograph I, p. 186. 



