Maryland Geological Survey 135 



4. The high percentage of heavy minerals, especially the rather large 

 proportion of magnetite. 



Finally, there are to be especially noted the black concretionary quartz 

 grains which, for the present, I shall not discuss (see p. 175, below). 



SAMPLE NO. 4 (FIG. D, p. 169) 

 Serial number : 14. 

 Field number : 4-7-13-1911. 

 Formation : Matawan. 



Locality : Chesapeake and Delaware Canal. 



Appearance : A fairly light-gray, very micaceous, . fine-grained, argillaceous sand; no 

 glauconite apparent. 



Mechanical Analysis 

 Sample 7.510 gm. 



Per cent of 

 sample 



Sands 68.1 



Silt 1.1 



Clay 29.5 



Total 98.7 



Per cent of 

 total sands 



Coarse sand 0.4 



Medium sand 1.4 



Fine sand 3.1 



Very fine sand .- 72.8 



Extra fine sand 21.4 



Total 99.1 



Per cent of 

 very fine sand 



Light 88.4 



Heavy 9.8 



Total 98.2 



Magnetic Separation 



Magnetic 98.1 



Non-magnetic ") 



Magnetite J 



Total 100.0 



DESCRIPTION OF PRODUCTS 

 A. Under the Hand Lens 



I. Coarse Sand 



Consists of 13 flakes of white mica and one very lustrous black carbonaceous flake. 



II. Medium Sand 



Almost all mica, mostly white with some brown and pale green flakes. Carbonaceous 

 grains. No quartz could be found. 



III. Fine Sand 

 Same composition as the preceding. 



IV. Very Fine Sand 

 See microscopic study of parts. 



