Maryland Geological Survey 153 



description of products 



A. Under the Hand Lens 



I. Coarse Sand 

 Nine grains of milky quartz, some very rough, others rounded but strongly coroded. 

 Several black carbonaceous flakes. 



II. Medium Sand 

 Much like the coarse sand, with some glossy quartz in small angular grains, with 

 more well rounded grains than the coarse sand, some mica, and much black carbonaceous 

 matter mainly fragments of wood. 



777. Fine Sand 

 Very much white mica and some chlorite. Most of the quartz is sharply angular but 

 there are still some rounded grains. There are a few grains of heavy minerals, zircon, 

 garnet, etc. Very much black carbonaceous matter as above. 



7T'. Very Fine Sand 

 Silver-gray with much mica and much line carbonaceous matter. It is darker than the 

 extra fine sand which apparently contains little carbonaceous matter. 



B. Under the Microscope 



I. Very Fine Sand 



(1) Light 



Quartz : feldspar = 95 + : 5 — . 



It is hard to count the feldspars in this sample on account of the aggregate polariza- 

 tion of many grains which probably are decomposing feldspars but which cannot be 

 identified. However, this should be regarded as an essential character of the rock and 

 with the low percentage of feldspar shows that the decay of the feldspars had advanced 

 far in this sample. 



There is a great variety of feldspars present including some plagioclase. 



The material is characterized by a dirty yellowish staining of the grains neither 

 ocherous nor glauconitic but in a very few cases looking like remnants of a glauconitic 

 stain. There are a few chloritic grains which, however, show aggregate, incomplete, or 

 undulatory polarization, and some very pale greenish-yellow without noticeable bire- 

 fringence. 



There is considerable muscovite. No glauconite was found. 



(2) Heavy 1 

 (a) Magnetic 

 Dominantly muscovite with abundant chlorite and biotite. A very little garnet and 

 tourmaline were found. 



(b) Non-magnetic 

 Zircon. 



II. Extra Fine Sand 

 Fine grayish-white sand. Quite pure, unstained quartz and feldspar with some 

 scattered carbon and a few grains of green chlorite in evidence. 



III. Silt 

 Darker gray, more micaceous than II. Under the microscope like the extra fine sand 

 with more carbonaceous matter and more mica. There are many of the pale yellow 

 chloritic grains that were observed in the very fine light portion. 



IV. Clay 

 Pure blue-gray. Unusually rich in the fibrous, dirty-colored, polarizing material found 

 so characteristic of the clays. 



1 This was the first sample examined for minerals so that the identification is probably 

 not complete. 



