OmCIN AND Foli.MAHlON (»K SOILS. 1-1 



decomposable rock than granite. It passes tlirougli talcose 

 gneiss into 



Tak'OSC Schist, which resembles mica-scliist in colors 

 and in facility of si>litiing into slabs, but has a less glis- 

 tening luster and a soapy feel. 



C'hloritic Schist resembles talcose schist, but has a less 

 unctuous feel, and is generally of u dark green color. 



Related to the above are Steatite, or soajystone, — nearly 

 pure, granular talc; and Serpentine rOCk, consisting 

 chiefly of serpentine. 



The above are tlie more common and wide-spread si- 

 licious rocks. By the blending together of the different 

 members of each series, and the related members of the 

 different series, and by the introduction of other minerals 

 into their composition, an almost endless variety of si- 

 licious rocks has been produced. Turning now to the 



Crystalline Calcareous Rocks, we have 



Granular Limestone, consisting of a nearly pure car- 

 bonate of lime, in more or less coarse grains or crystals, 

 commonly white or gray in color, and having a glistening 

 luster on a freshly broken surface. The finer kinds are 

 employed as mo?niinent(d marble. 



Dolomite has all the appearance of granular limestone, 

 but contains a large (variable) amount of carbonate of 

 magnesia. 



The Fragmental or Sedimentary Rocks are as fol- 

 lows: 



Conj^lomerates have resulted from the consolidation of 

 rather coarse fragments of any kind of rock. According 

 to the nature of the materials composing them, they may 

 be granitic, syenitic, calcareous, basaltic, etc., etc. They 

 pass into 



Sandstones, wliich consist of small fragments (sand), 

 are generally siliciovs in character, and often are nearly 

 6 



