NOTES ON THE MICROSCOPIC STRUCTURE 363 



Sandstone, Maynard, East Longmeadow, Mass.— Cannot 

 be distinguished from the Kibbe stone. 



Sandstone, Worcester, East Longmeadow, Mass. — Quartz 



and feldspar are the constituent minerals. The quartz is 

 cloudy from minute cavities and is more or less stained. 

 The feldspars are almost completely kaolinized. The 

 cementing material is apparently lime and iron. Fibrous 

 mineral abundant. 



Sandstone, Brainerd Quarry Company, Portland, Conn. — 



Quartz, feldspar and occasional scales of decomposed mica, 

 are the constituent minerals. The quartz represents about 

 two-thirds of the bulk of the stone. The grains are angular, 

 and, as a rule, clear. Acicular crystals and included gas 

 pores and liquid are not common. The feldspars are almost 

 all of them completely kaolinized. Carbonate of lime is a 

 resultant mineral of this decomposition. Iron is the chief 

 cementing material, with the carbonate of lime. Some of 

 the feldspars are fresh enough to show the original cleavage 

 lines. The muscovite has lost most of its special properties 

 and appears more like talc There is much interstitial 

 '* mud " which seems to be made up of aggregations of iron 

 and fine silica. 



Sandstone, Belleville, New Jersey.— No essential differ- 

 ence is noted between this stone and that from Portland. 



Sandstone, Berea, Ohio.— Quartz seems to be the principal 

 mineral in this stone. The sole exceptions appear in the 

 yellow spots of hydrous oxide of iron. The quartz is in 

 fine, angular and even-sized grains, lying in close contact. 

 The stone seem to be friable and imperfectly cemented 

 together. There is no reaction for carbonate of lime. 



Sandstone, Bristow, Virginia.— Quartz and feldspar are 

 constituent minerals. The quartz is rather cloudy. The 

 feldspars are almost completely kaolinized. Enough re- 

 mains to show that they were plagioclase. The cementing 

 material is hydrous oxide of iron and carbonate of lime. A 

 great deal of muddy interstitial matter shows clots of iron. 



