Reviews 



Underground Water Resources of Iowa. By W. H. Norton and 

 Others. Iowa Geological Survey. Vol. XXI, Annual 

 Reports for 1910 and 1911. Pp. 28-1186. 



This report treats of the sources, conditions of occurrence, chemi- 

 cal ingredients, and amount of the underground waters of Iowa. The 

 waters are considered under three heads: (i) artesian waters, which 

 rise within the tube because of hydrostatic pressure; (2) waters of the 

 country rock; and (3) waters of the drift. Important conclusions 

 regarding these, especially the first, are based upon chemical analyses, 

 deep drillings, and the structure and lithology of the rocks. The state 

 is arbitrarily divided into eight districts, and more or less specific informa- 

 tion is set forth for each. 



The principal aquifers noted are the Saint Peter and the Prairie du 

 Chien formations of the Ordovician system, and the Jordan, Dresbach, 

 and underlying sandstones (unexposed) of the Cambrian. Superiority 

 is generally ascribed to the Saint Peter, chiefly because it is efficient, 

 accessible, and identifiable over about three-fourths of the state; it, 

 however, is not tapped in the southwestern part, where it lies at great 

 depth and its waters are likely to be mingled in the wells with the highly 

 mineralized waters of the Carboniferous strata. In the western part 

 of the northwest district the Dakota sandstone is a boon to good water 

 conditions. The Paleozoics, especially the lower members which out- 

 crop in Wisconsin, Minnesota, and Northwestern Iowa, dip gently to 

 the southwest in the form of a wide, open trough which leaves the state 

 at the southwest corner. The strata, however, have sufficient varia- 

 tions in structure and lithology to make forecasts somewhat uncertain. 

 The water of artesian wells of the northeast quarter of the state is said 

 to be the purest. 



Reasonable consideration is also given to the water conditions of 

 the country rock and drift, and a list of typical well-logs in the townships 

 of each county is published. But the main stress is laid on municipal 

 and industrial supplies, as evidenced by the frequent advices and 

 cautions concerning the procuring of the same. Maps and structure 

 sections clarify the geologic horizon of the important aquifers. 



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