AETESIAN WELLS IN NORTH AND SOUTH DAKOTA. 531 



west from the iiioutli of the Big Sioux River at the southeast corner of 

 South Dakota ; (3) depths of the wells ; (4) tlieir pressure at the surfiice, 

 wherever it has been obtainable, in pounds per square inch ; (5) the corre- 

 sponding height or head to which the water would rise above the surface ; 

 (6) the altitude, with reference to the sea-level, of the source of the arte- 

 sian water in the Dakota sandstone ; (7) the altitude of the surface ; and 

 (8) the height of the computed head of water above the sea. 



The flow of water from the Dakota sandstone at Devils Lake is found 

 exactly at the sea-level, but the top of the sandstone formation is 39 feet 

 higher. At Jamestown the flow rises from a deptli of 76 feet below the sea- 

 level, indicating that the top of the Dakota sandstone there sinks slightly 

 lower than at Devils Lake. Along the distance of 8.5 miles from north 

 to south between these points its level is probably nearly constant, and 

 borings at intervening towns, as New Rockford and Carrington, will douljt- 

 less find artesian water at or slightly below the sea-level. Farther south 

 the top of the sandstone and its water supply are found throughout a 

 large district of South Dakota and the south edge of North Dakota at 

 a plane from 2.50 to 450 feet above the sea. Continuing still southward, 

 from Woonsocket to the Missouri River the water-bearing stratum rises to 

 altitudes from 558 to 818 feet above the sea, the highest levels being at 

 Meckling and Vermillion, the most southeastern localities of this list. 



The same southeastward ascent of the Dakota sandstone reaches to 

 its outcrops on the southwest side of the Missouri in Dakota County, Nebr., 

 whence its name is derived, opposite to the southeast corner of South 

 Dakota. There, and at other extensive outcrops in western Iowa and east- 

 ern Nebraska, having approximately the same elevations as the surface at 

 Vermillion and Yaukt(in, the water coursing through this sandstone finds 

 outlet in springs; and these avenues of discharge explain the gradual 

 reduction in the altitude of the head of water above the sea-level as the 

 series of wells is followed from north to south and from west to east. 

 Somewhat uniform altitudes of 1,619 to 1,743 feet are recorded as the 

 heights to which water would rise in pipes for all the wells where pressure 

 is reported, from Jamestown to Huron and Woonsocket, excepting those 

 west of Huron, which will be considered later, and the well at Ashton, 



