GEOLOGY OF SOUTHWESTERN IOWA. 335 



the Upper or unproductive coal-measures, it will be correctly 

 inferred from what has been before written, that the hope 

 of finding coal within its limits should be based upon 

 explorations at considerable depth beneath its surface, which, 

 to save useless labor, should be commenced in the valleys. 

 If such enterprises as have been recommended on previous 

 pages for Madison county should prove successful there, those 

 who shall commence similar labors in the valley of Grand 

 river or elsewhere in Union county, will have additional 

 reason to expect similar success. 



The strata exposed in this county are referred to a horizon 

 a little below the middle of the full series of Upper coal- 

 measure limestone, as exposed near Winterset, and shown in 

 the section measured near that place, which will be found 

 represented on a previous page. They are also referred to 

 about the same horizon which those strata belong to, that 

 contain the thin bed of coal found there; but that bed of coal 

 seems to have entirely thinned out to the eastward, so that it 

 is not represented at all in the valley of Grand river, and will 

 probably not be found at all in Union county. Thus, 

 although strata in those counties that are geologically equiva- 

 lent to these, do contain a bed of coal there, yet a supply of 

 that valuable material, if found at all in Union county, should 

 be sought for by deep mining. 



There is a sufficient area of woodland in Union county to 

 meet the present wants of the inhabitants for fuel, yet the 

 proportion in the western half of it is small. In the eastern 

 half, however, especially along the valleys of Grand river and 

 its principal branches, the supply of wood is quite sufficient 

 for present and prospective use. The county is well supplied 

 with water from its numerous streams, and wells of water 

 may be obtained almost anywhere at moderate depth, even 

 upon the highest surfaces. The soil is of that variety known 

 as drift soil, except the small proportion of alluvial soil in 

 the valleys. It is everywhere of the same fertile and excellent 

 character as that which characterizes the whole region of 

 southwestern Iowa. 



