398 REPORT ON NATIONAL MUSEUM, 1886. 



tionoftbe State south of Indianapolis. But few quarries of impor- 

 tance lie to the north of this point, and when worked the stone is used 

 principally in the manufacture of quicklime. At Anderson, in Madison 

 County, a light-colored, fine-grained stone occurs in beds of from 4 to 

 12 inches in thickness, which is used locally for flagging and general 

 trimming purposes. 



Iowa. — Although this State abounds in limestones and dolomites to 

 the exclusion of almost all other varieties of building stone, but little 

 of the material now quarried is of such a nature as ever to acquire more 

 than a local reputation. Though having altogether more than three 

 times the number of quarries found in Illinois, these are mostly small 

 affairs, and the value of the total product is but little more than one- 

 half that of the latter State. At the time of the taking of the Tenth 

 Census the whole number of quarries in the State was 131, of which 128 

 were of limestones and dolomites, and the remaining 3 of sandstone, 

 which are mentioned on p. 449. 



At the present time the most important quarries are situated in the 

 Niagara division of the Upper Silurian formations, in the vicinity of Stone 

 City, Jones County; Farley, Dubuque County, and in various portions 

 of Jackson, Cedar, Clinton, and Scott Counties. The Jones County 

 stone is a very light-colored, fine-grained and compact bituminous dolo- 

 mite. That from Farley is very similar in general appearance, but con- 

 tains less bituminous matter. In the small blocks received at the 

 Museum the stones appear of good quality, but we have had no op- 

 portunity of learning their weathering qualities. 



A finely crystalline light colored limestone of sub- Carboniferous age is 

 quite extensively quarried near Burlington, in Des Moines County. 

 According to Professor McGee* this stone, which is practically identi- 

 cal with that of Keokuk, in Lee County, is used chiefly for common 

 masonry, and only occasionally for dressed work. The upper beds are 

 " nearly white in color, fine, compact, homogeneous, and hard, with a 

 choncoidal or splintery fracture, like the so called lithographic lime- 

 stone of nearly the same geological age. This stone has been used to 

 some extent for ornamental purposes, but contains too many incipient 

 fractures, and is too liable to unexpected disruption to be of special 

 value." 



Near Le Grand and Montour, in Tama County, there occurs a magne- 

 sian limestoue of the same age as that just described, which is flue 

 grained, compact, and generally buff or whitish in color. The coarser 

 portions are extensively used for heavy masonry, while the finer grades, 

 which are often beautifully veined with iron oxides, are used for orna- 

 mental work under the name of " Iowa marbles." Some of the stone 

 from this locality is oolitic. Similar stoues are extensively quarried at 

 Iowa Falls and at Humboldt and Dakota, in Humboldt County. Lime- 



* Report of Tenth Census, p. 261, 



