Maryland Geological Survey 133 



description of products 



A. Under the Hand Lens 



I. Coarse Sand 



(a) Fairly well rounded grains of quartz mostly white opaque, almost all, however, 

 much pitted and corroded as if by solution. 



(b) Next in abundance are rounded concretions formed of grains of fresh-looking 

 glauconite, quartz, etc., cemented by limonitic matter. 



(c) Some of the quartz is of the black granular concretionary type (cf. Sample No. 13) 

 suggesting secondary origin in the sediment. 



II. Medium Sand 



(a) Angular quartz grains predominate, though there are still some very well rounded ; 

 there is also more glassy, less opaque quartz. 



(b) The glauconite is mostly in rounded grains : most of those that are not rounded 

 suggest by the irregularity of their form a secondary concretionary origin from 

 botryoidal grains. There are a very few normal botryoidal grains all somewhat rounded. 

 The proportion of glauconite is small. 



(c) There are limonitic sand concretions as in the coarse sand but more rough and 

 irregular, less rounded. 



(d) Considerable white mica. 



(e) Black carbonaceous fragments. 



(f) Shell (?) fragments stained brown. 



III. Fine Sand 

 Its general appearance is dark greenish-black, speckled. 



(a) Quartz predominantly glassy and angular. 



(b) Glauconite as in preceding but much more abundant. 



(c) Limonitic sand concretions as in preceding. 



(d) Much white mica. 



(e) Many black carbonaceous fragments. 



IV. Very Fine Sand 

 General appearance much like the fine sand. 



V. Extra Fine Sand 

 Dark blackish-gray. Appear much like the preceding portion. 



B. Under the Microscope 



I. Very Fine Sand 



(1) Light 

 Quartz : feldspar=90 : 10 



The feldspars appear unusually decomposed. No plagioclase was found. 

 There is little glauconite and mica left. 

 Both quartz and feldspar show much ocherous staining. 



A grain was noted made up of individual grains of quartz differently oriented in a 

 cloudy quartz cement of homogeneous orientation, believed to be derived from quartzite. 



(2) Heavy 



(a) Attracted at 2000 ohms heavier than 3.002. 



The abundant minerals, in the approximate order of their frequency, are : 

 Abundant. — Glauconite in translucent to nearly opaque olive-green grains, chlorite, 

 biotite unusually abundant, epidote. 



Rarer. — Garnet, tourmaline, muscovite, staurolite, rutile. 



(b) Attracted at 2000 ohms lighter than 3.002. 



Not especially studied. Almost pure glauconite with some mica. 



(c) Full-current product. 



A brownish-yellow, micaceous sand. 



Abundant. — Muscovite, chlorite, quartz. This is doubtless separated here on account of 

 its heavy ocherous stain. 



Rarer. — Tourmaline, epidote, biotite, asbestos ( ?) . 



