GEOLOtiY. 39 



the statuary marble. From Thomastown, Maine, both 

 marble and common lime are procured for Boston mar- 

 ket in abundance. In the western part of New Eng- 

 land, and the eastern part of New York, is an extensive 

 range, less ancient, than those already mentioned, and 

 less recent than that which constitutes the principal 

 rock in the western part of New York, and the country 

 between that and the Mississippi. 



Gypsum, (plaster of Paris,) is one of those rocks 

 which are found in great abundance in a few places 

 upon the earth, but are not common. Nova Scotia, 

 the western part of New York, the vicinity of Paris, 

 France, and a few other places, contain inexhaustible 

 deposits of it. None of consequence has yet been 

 discovered in New England. 



Several varieties of this rock are found in abundance, 

 some of which are transparent, crystallized, and beauti- 

 ful. A common and abundant variety of crystallized 

 gypsum is called selenite, which is in transparent plates 

 or laminae, and resembles mica, and with that has been 

 called isinglass. Their resemblance, however, is mere- 

 ly in their external appearance, their elements being 

 entirely different. Mica is also highly elastic, while 

 selenite is not so, and cannot be bent without breaking. 



Gypsum has numerous uses, the most important of 

 which is in agriculture. It has the power of entirely 

 changing the character of some soils, and rendering the 

 most barren, gravelly plains highly fertile. It is more 

 favorable to the growth of clover than any other plant, 

 but promotes the growth of potatoes, Indian corn, and 

 on some soils, of winter grain. It is also used for vari- 

 ous ornamental purposes as a plaster. 



The ingredients of which gypsum is composed, are 

 lime, sulphuric acid, and water. 



Soapstone is composed of talc, with a small mixture of 

 quartz. Both talc, and the rock which it composes are 

 soft, and easily wrought into any shape required by 

 their numerous uses. This rock is hewn into blocks by 

 an axe, separated into slabs by a common saw-mill, or a 

 hand-saw, turned into cylinders or other circular forms 

 by a lathe, and smoothed by a plane. 



