BUILDING AND OKNAMENTAL STONES. 421 



Minnesota. — According to Professor Wiuchell more than half the 

 State of Minnesota is underlaid by that general class of rocks — the 

 crystalline — to which granite belongs. In the northern part of the State 

 there are large exposures of very fine light-colored granites, but being 

 beyond the limits of settlements and roads those in the southern and 

 western part, in the country bordering along the Mississippi and Min- 

 nesota Rivers, are of more especial interest and importance. These last 

 have been somewhat quarried and the materials can be seen in some of 

 the principal buildings in various parts of the State, as well as in cities 

 beyond the State limits. The first quarry in these rocks in Minnesota 

 was that now owned by Breen & Young, at East Saint Cloud, Sher- 

 burne County. 



This was opened in 18G8, and the stone first taken out was used in 

 the corners, steps, and trimmings of the United States custom house 

 and post-office in Saint Paul. Three kinds of stone were taken out 

 and used indiscriminately, and all of them may be seen in the building 

 first erected. The variety now more generally used is of a gray color 

 and uniform texture. The crystalline grains are rather fine, so that the 

 texture is close. The color, however, is sometimes disturbed by the 

 appearance of greenish spots of the size of butternuts or even as large 

 as 6 inches in diameter, caused by segregations of a green chlorite. 

 ''About one-third of the whole rock is made up of quartz, and two-thirds 

 of the remainder of orthoclase. About one-half the remainder is horn- 

 blende and the residue is divided between the other minerals, the chlo- 

 rite predominating." An occasional graiu of a triclinic feldspar is 

 present together with magnetite and pyrite in minute crystals.t 



"The red granite from East Saint Cloud is not very different from 

 the foregoing, but the feldspar is mainly flesh red and all the grains 

 are coarser." It also has a higher per cent, of silica, a fact that has 

 been discovered practically by the owners, who had given up the gen- 

 eral use of it because of it being more costly to work. " * * * In the 

 winter of 1874-5 a block weighing ten tons was taken out of the red- 

 granite quarry, about 3 miles west of Saint Cloud, for a monument 

 base. * * * It was very fiue, and greatly resembled the Scotch 

 granite in color, grain, and polish. At the point where this was taken 

 out the granite rises about 20 feet above the general surface and spreads 

 over more than an acre. A similar red granite occurs at Watab (in 

 Benton County), and has furnished several handsome monuments." A 

 light-gray granite also occurs here.* 



At Sauk Rapids, in the same county, there is found a fine-grained 

 gray granite closely resembling the gray variety from East Saint Cloud. 



* See Geol. and Natural Hist. Survey of Minnesota, Vol. I, pages 142-148. 



t These rocks are designated in Professor Winchell's report above referred to as 

 "Syenites." According to the system of classification now generally adopted, they 

 are rather hornhleudic or hornblende-biotite granites, as designated by the author in 

 the census report, p. 90. The name syenite, as already noted, is applied to a quartzless 

 rock (see pp. 308 and 430). 



