4db NATURAL HISTORY. 



States. That species from which the German pipes are 

 made occurs in Cologne, Alsace, and Nassau. 



Limestone Clay is ochreous-yellow or brown, often 

 containing grains of quartz: is used by masons, etc., for 

 building purposes. 



Potter's Clay is gray or bluish-gray, very sectile. 



Lithomarge is a compact clay, of fine, smooth tex- 

 ture, also grayish-blue, and very sectile. Sometimes 

 contains mica, and absorbs a great deal of water ; after 

 drying, contracts, and becomes very hard. 



Fuller's Earth, Soapstone, etc., claim a place here. 

 All clays are made subservient to the use of man in 

 making Delft ware and common pottery ; for fulling or 

 washing cloth, making tiles, and cement or plaster, refin- 

 ing sugar, etc. Lithomarge and Tuesite, which are im- 

 pervious to water, are used as cement to line the inside 

 of cisterns. Clay soils are damp and cold, consequently 

 unfruitful; burnt clays are the best compost for such. 



Porcelain Clay or Kaolin is derived from the decom- 

 position of feldspar, as already stated; pale-colored, 

 opaque : placed on the tongue, adheres to it ; feels soft 

 and dry ; structure compact, seldom crystalline. Color 

 white, verging into gray or red ; occurs in nests among 

 gneiss, granite, and mica-slate. Found in the United 

 States in many places ; the foreign porcelain clay occurs 

 in Saxony, France, and England, but that of China and 

 Japan is the finest. 



Steinmark, Myol'ui or White Lithomarge is a pale, 

 opaque, compact clay, of fine, smooth texture ; feels 

 somewhat greasy, and, placed on the tongue, adheres to 

 it. Its colors are white, grayish, bluish, often reddish, 

 white or ochre color, with a shining streak. Found in 

 the serpentine and topaz rocks, etc., of the German 



