5i2 



/. K. PRATHER 



lacked some of the chemical components which go to make up the 

 glauconite. The slides were prepared by boiling in Canada balsam 

 to render them hard before grinding down. 



In a sample examined from Bed 2, Gyphets vesicularis bed, of the 

 Navesink, the purest sample of glauconite I had, there were five 

 specimens of Foraminifera (Nautiloid type, Trochoid type, Nucularia 

 type, and Nodosaria type), but the shells were still intact, and the 

 shape and size differed considerably from the glauconite grains. 



Some glauconite grains are solid, while others have fine lines 

 running across them, as if they had been further divided up. Some 

 grains would seem to indicate by their shape that they had been formed 

 inside a shell, but other evidence of this seems to be lacking. 



TABULAR LIST OF SLIDES 



Bed 1 



Slide 



Nav, 

 Nav, 

 Nav 

 Mat 



Mat 

 Mat 



Nav, 



Nav. 



Nav. 

 Nav 



Nav. 

 Nav, 

 Nav 



Nav 



Nav 

 Nav 

 Nav 



Haz 



Nav 

 Red 



Ca 



E 4 

 Ca 



P 



E5 

 typ. 



gyp- 



Bi 



G 3 

 G2 



Gi 

 Ai 



24 



25 

 26 



13 



Two altered grains of glauconite surrounded by fresh grains 



Same as above, but with more alteration 



Glauconite altered to magnetite 



Contains glauconite, muscovite, microcline, quartz, rutile in 

 quartz,' glauconite altered to iron 



Same as preceding 



Same as two preceding, but smaller mineral particles 



Fibrous glauconite, gypsum surrounded by glauconite, and 

 inclosing grains of quartz and glauconite. 



Altered and unaltered grains and a clay ground-mass 



Much clay, alteration to clay, and also to magnetite 



Glauconite unaltered, and partly altered to magnetite. 



Abundance of quartz and feldspar, and little glauconite 



Alteration chiefly to hematite 



Grains of microcline and mica coated by glauconite, which is 

 also partly altered to magnetite, masses of pyrite (secondary), 

 fibrous glauconite 



Glauconite coating mica, rounded, oval, semicircular, and rec- 

 tangular grains of glauconite, and a cross-section of a Fora- 

 minifera mentioned above, grains of quartz, orthoclase, micro- 

 clene, pyroxene, mica, plagioclase, a quartz grain coated by 

 glauconite which is partly altered to magnetite 



A large grain of glauconite made up of aggregates which readily 

 separate; also contains mica, quartz, gypsum, glauconite, etc. 



Microclene coated by glauconite and shattered grains of quartz 

 'and feldspar 



Quartz coated by glauconite, round grains of glauconite with 

 small grains of magnetite regularly arranged, also mica, horn- 

 blende, and pyroxene 



Composed of glauconite grains more or less altered; some 

 grains appear to be concretions, while others look as if they 

 may be sections of Foraminifera 



A feldspar grain covered by fibrous glauconite 



Alteration to hematite and to limonite 



1 Nav. = Navesink; Mat. = Matawan; Haz. = Hazlet Sand; Red. = Redbank. 



