BUILDING STONES. 183 



Stone City and Berea stone.] 



quarries at Frontenac, in Gooclhue county. They both stand 77. This 

 stone has been employed in the fronts of several large business blocks in 

 Minneapolis, the principal being the Casey block, between Washington 

 avenue and Third street, on Mcollet, and the Hennepin block on Hennepin 

 avenue. 



The Stone City stone, from Iowa (No. 40), is from the same formation 

 as the Lemont stone, but it has lost its original color (which is that of the 

 Lemont stone) by long exposure in the bluffs of the river where it is wrought. 

 The acquired color penetrates the formation there to a depth greater than 

 that reached by any of the quarries. It is now light buff, which is the color 

 of nearly all of the limestones, where exposed in the "driftless area," what- 

 ever they may be where they are buried under the drift sheet at other 

 places. As quarried at Stone City (in Jones county) the Niagara seems to 

 be much more a magnesian limestone than at Lemont in Illinois, the inso- 

 luble portion being less than one per cent., and its content of lime and mag- 

 nesia together being over 95 per cent. As compared with the Lemont stone 

 for purposes of construction, the tests that have been made by the survey 

 show the Lemont stone is much stronger under pressure,* but that it 

 weathers much more rapidly, The latter is probably due to its larger per- 

 centage of alumina, which gives it a finely striped surface when dressed on 

 the edges of the bedding, and produces, but much more slowly, the same 

 laminated disintegration as is seen in the Trenton limestone (No. 27). The 

 Stone City dolomitic limestone was employed in the construction of the Bos- 

 ton block and the Windom block, at Minneapolis, and for the curbing of 

 the paved streets. 



The Berea sandstone, Number 41 of the table, is one that has a wide 

 reputation in the United States for its excellence in all kinds of building. 

 It has a uniform color and rather fine and arenaceous grain, with occasional 

 feldspar (?) and muscovite particles, the cement being carbonate of lime. 

 This may be seen in numerous buildings in St. Paul and Minneapolis, as well 

 as in Stillwater, Red Wing, Wiriona and other cities. The Syndicate block, 

 at Minneapolis, is the largest in the state wholly faced with this stone. 



*The Lemont stone is exceptionally strong for a limestone. 



