CHAPTER IX. 

 WATER PROVINCES OF THE UNITED STATES. 



Principal Water Provinces. - - There are wide differences in 

 the underground water conditions in the different parts of the 

 United States. These are due, in a large measure, to the diversi- 

 fied character of the water-bearing materials and to the variations 

 in geologic structure. 



An area throughout which the underground water conditions 

 are essentially similar or, more especially, in which the occurrence 

 of ground waters is governed by the presence of some particular 

 water-bearing bed or of some geological structure favorable to the 

 accumulation of ground waters, is known as a ground water 

 province. 



There are about a dozen great ground water provinces in the 

 United States; the Drift Province, the Weathered Rock Province, 

 the Atlantic Coast or Coastal Plain Province, the Piedmont 

 Province, the Appalachian Mountain Province, the Mississippi 

 Basin Province, the High Plain Province, the Rocky Mountain 

 Province, the Great Basin Province and the Pacific Province. 

 Several of the major provinces may be subdivided with a number 

 of smaller provinces, and the bounds of one often merge into 

 those of another. Two of them, the Drift and the Weathered Rock 

 provinces, are superficial and overlie the more fundamental, 

 though no more important, provinces based on the underlying 

 geology. 



Area of Glacial Drift. - - This area is bounded on the south by 

 a line which, starting at Nantucket, passes through Martha's Vine- 

 yard, Long Island, across New Jersey, northwestward across 

 Pennsylvania into New York, then southwestward across Pennsyl- 

 vania and Ohio to the vicinity of Cincinnati, where it crosses the 



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