MINERALS— NON-METALLIC 159 



buildiuu' and pulilir works. 'I'ho essential (lualitics of huikliug stoues are strength, 

 durability, wdrkabilil.v. cdlor and bcani.v. 



Ot'ourrent'e — Atcordin.ii' to Rowe. who has made the ouly survey of this re- 

 source, Montana is well supplied with many varieties of good building stones. 

 East of the Rocky Mountains the stone is mostly sandstone; in the western part 

 of the state, granite, quartzite, limestone and phyllite are the principal kinds of 

 rock. In a few places, especially in the western third of the state, volcanic 

 ash is used as a building stone. Rowe states a sandstone quarry is found at 

 almost every town from AVibaux. in eastern Montana, to Livingston. M."0 miles 

 west, while from Helena west to the Bitter Root mountains, both north and south. 

 are found granite, phyllite, and quartzite in large quantities and at many localities. 



Sandstone quarries are mentioned liy Rowe in Beaverhead, Carbon, Cascade, 

 Hill. Custer. Fergus. Sweet Grass. Stillwater. Yellowstone and Park comities. 

 The Beaverhead. Stillwater and Yellowstone sandstones pronounced among the 

 best in the state. Some of the best buildings in Salt Lake were constructed of 

 Beaverhead county stone, and the softer, purer white variety has been used as a 

 flux at Anaconda. Rowe says this softer kind is without doubt the purest 

 quartz sandstone in the state, and when crushed resembles glass sand, for which 

 purpose it would undoubtedly be good. The original state capital at Helena was 

 built of Stillwater county sandstone. 



Granite quarries are mentioned by Rowe in Lewis and Clark. Jefferson, 

 Silver Bow and Ravalli counties The wings of the state capital at Helena were 

 constructed of Jefferson count.v granite. 



The finest colored quartzite in the state is probably found in Beaverhead 

 coimty. according to Rowe, and the largest quantity in Missoula county. In 

 Beaverhead count.v. he says, is found the best volcanic ash building stone in the 

 state. Other counties named as being among the chief producers of this stone are 

 Gallatin. Ro.sebud, Missoula and Ravalli. The best quarry of phyllite or silicious 

 slate is in Flathead county. This stone is also found in Missoula county. 



CLAYS 



Uses — For pottery ware including porcelain, china, granite and earthenware, 

 various kinds of brick, floorin.g. terra cotta in moldings and decorations, for irri- 

 gating and drain tile, water conduits, sewer pipes, ventilating flues. In the indus- 

 trial arts for crucibles, retorts, furnace and stove linings, puddling hearths, smelt- 

 ing furnaces, glass pots, insulating materials in electrical engineering, filling for 

 walls, sizing and filling for paper, cement manufacture, mineral paint and paint 

 adulterants and experimentally in manuf.icture of aluminum. Among the most 

 important kinds of clay are china clay, kaolin and indianaite. usually mixed with 

 feldspar and u.sed in whiteware. porcelain, tiles, insulators and for sizing and 

 weighting paper. Ball clay and ware clay, a white burning plastic clay used in 

 pottery industry to give strength and plasticity to the non-plastic clays. Fire 

 clay, chiefly residual or sedimentary clay possessing high refractoriness, used 

 in fire liricks, furnace linings, retorts, crucibles, tiles, terra-cotta, pressed brick, etc. 

 Much of the fire clay produced comes fi-om beneath coal seams. Brick clays, 

 impure plastic clays usually with a high percentage of fluxing impurities which 

 cause them to burn to a hard product at a low temperature. Stoneware clay, a 

 refractory or semi-refractcn'y vitrifying clay of sufficient tensile strength and 

 plasticity to l>e workable on a poiti-r's wheel. Fire proofing and hollow brick 

 clay should have rather high plasticity, fair tensile strength and should burn to a 

 good hard but not vitrified body at a comparatively low temperature. "Washed 

 kaolin and certain fine-textured, fairly pla.stic sedimentary clays free from sand 

 are iised to give l)ody, weight and firmness to various kinds of paper. Cement clay 



