Maryland Geological Survey 147 



description of the products 



A. Under the Hand Lens 

 I. Lime-free Residue 



This separates in water into two very distinct parts : 



(1) Very glauconitic clear sands. 



(2) Dark brown clay (probably with considerable limonite) which floats on top. 



II. Coarse Sand 

 Eight grains of quartz with glossy, pitted surfaces ; one of them is stained green ; one 

 is sugary and stained brown. Some leaf fragments. 



///. Medium Sand 

 Glossy, angular quartz ; some sugary grains stained brown as in II ; almost no grains 

 stained green. Very fresh botryoidal glauconite ; some rounded grains of glauconite. 



IV. Fine Sand 

 Much of the glauconite is rounded and more than in III is faded yellowish ; otherwise 

 the glauconite is as in III. There is very little mica. 



V. Very Fine Sand 

 The glauconite is almost all rounded, much of it weathered yellowish. The grains of 

 quartz are all angular. 



VI. Extra Fine Sand 

 General appearance green. The glauconite. is half yellowish, half fresh, blue-green. 



B. Under the Microscope 



I. Very Fine Sand 



(1) Light 

 Quartz : feldspar = 90 : 10. 



The determination of the proportion of feldspars present is made difficult by the 

 presence of minerals in various stages of decomposition, towards a mass with complex 

 aggregate polarization, which may be derived from feldspars. Difficulties are also afforded 

 by cloudy grains which may be quartzite. Most of the feldspars are much weathered. A 

 grain of plagioclase was noted. There is much irregular glauconitic staining of grains, 

 and glauconite in thick seams along cleavage cracks. Many grains of glauconite are 

 present. 



(2) Heavy 

 (a) Attracted at 2000 Ohms, S. G.> 3.002 



More than half glauconite. Magnetite largest part of remainder, many of the grains 

 well rounded. Red garnet a little less common than magnetite. Epidote and staurolite 

 rather common. Some chlorite. Green zircon ( '!) . 



(To) Attracted at 2000 Ohms, H. G. < 3.002 

 Almost pure glum unite, in well rounded or botryoidal grains, opaque to slightly trans- 

 lucent, free from coarse-granular inclusions. The botryoidal grains are very scarce. 

 There is. iu addition, a very little muscovite and quartz. 



(c) Attracted at Full Current 

 Tourmaline, rutile, augite, biotite, muscovite, green zircon, chlorite, glauconite. The 

 glauconite in this portion is in rough, irregular grains, cloudy to opaque, mostly full 

 of black mineral grains. Many of the grains that look like chlorite are found to have 

 undulatory to aggregate polarization indicating that they are in a transition stage from 

 or to chlorite. In view of the fact that glauconite is itself believed to be one of the 

 chlorites this may be of significance for the formation of glauconite. Two small, remark- 

 ably spherical grains of quartz are noteworthy. 



(d) Nonmagnetic 

 Most common enstatite, zircon, augite, hornblende, apatite, rutile, andalusite (?). The 

 good preservation of tile crystal form of the rutile is striking. 



