14 A TREATISE ON THE CONNECTION OF 



SILICEOUS MATTER. 



Great trails of the surface of ibe earth are of this 

 description, and very large masses of the under stratum 

 consist of the like substance : the former in the state of 

 loose sand, aijd the latter in an indurated or solid state, 

 called sand-stone or free-stone. It is, of all the earths, 

 the least retentive of moisture. 



MAGNESIAN EARTH. 



This is no where found in such quantities as to form a 

 soil of itself ; it is contained in different proportions, in 

 many soils, and constitutes a component part of stea- 

 tities, or soap rock. It is retentive of moisture to a cer- 

 tain degree. 



EARTH 



