BUILDING AND OKNAMENTAL STONES. 421 



Minnesota. — According to Professor Wiuchell uiorc tliau half the 

 Stato of Miunesota is uiulerhiid by that j^eiieral chiss of rocks — the 

 crystalliue — to which grauite belongs. lu 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 iii the southern and 

 western part, in the country bordering along the Mississipi)i and Min- 

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

 have been somev.iuit (puirried 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 Miunesota 

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

 bnrne County. 



This was opened in 1808, and the stone first taken out was used in 

 the corners, steps, and trimmings of the United States customhouse 

 and post-oftice 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 

 apx)earauce of greenish spots of the size of butternuts or even as large 

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

 ''About one-third of the whole rock is made up of quartz, aiul 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 grain of a triclinic feldspar is 

 present together with magnetiie and ijyrite in minute crystals.! 



"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 fine, 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 si)reads 

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

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

 light-gray granite also occurs here.* 



At Sauk Rai)ids, in the same county, there is found a fine-grained 

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



* Sec Geol. aud Natural Hist. Survey of Minnesota, Vol. i, pages 142-148. 



t These rocks arc designated iu i'rofessor Wincboll's report above referred to as 

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

 are ratlier liorubleudic or bornbleude-biotite granites, as designated by tlie author in 

 the census report, p. 90. The name si/cniic, as already noted, is ap^diedtoa quarti^lesa 

 rock (see pp. oOd aud 4o0). 



