312 COUNTY AND REGIONAL GEOLOGY. 



Economic Resources. The mineral resources at present 

 accessible in Madison county, consists almost entirely of its 

 stone. In this respect, it has few equals among the counties 

 of the State, and it probably possesses more accessible 

 material of this kind than all the other thirteen counties, 

 enumerated in a former chapter under the head of South- 

 western Iowa, except Clarke and Decatur counties. 



By reference again to the sections of the strata of this 

 county, already given, it will be seen that those which are 

 referred to the Middle coal-measures are almost destitute of 

 stone that is suitable for even the most common building 

 purposes. Consequently, in that part of the county occupied 

 by that formation alone. Such material is scarce : but the 

 case is far different in the other portions of the county, as 

 may be seen by referring to the strata represented by the 

 upper and middle portions of the Winterset section. The 

 majority of these strata, it will be seen, are limestone. Those 

 represented by the numbers from eleven to seventeen, inclusive, 

 are much more frequently exposed than any of the others, 

 and from these the greatest abundance of stone may be 

 obtained. All of it is suitable for lime, and nearly all, for 

 purposes of common masonry ; but some of the beds also 

 furnish excellent stone for dressing. Some fine stone for the 

 latter purpose may be obtained in the valley of Middle river, 

 in the western part of the county, but it is in the immediate 

 vicinity of Winterset that the finest stone for dressing has 

 yet been observed. No. 14 of the section there furnishes the 

 best quality, and being near the top of the valley-sides with 

 only slight depth of other material above it, is quarried with 

 comparative facility. The stone of this bed is in massive 

 layers, having an aggregate thickness of about six feet. It 

 is light-gray in color, yields readily to the workman's tools, 

 being uniform in texture, and endures exposure to the atmos- 

 phere and frost without damage. 



Considerable quantities of this stone have been quarried 

 and used in the town of Winterset and its vicinity; and the 

 finer qualities of it have in some cases been carried as far as 



