174 The American Geologist. September, 1905 
No. (5) is a brown sand but fine grained and contain- 
ing much fine clay. The grains of quartz and mica are 
also very small. Nos. (4) and (5) are part of the Bay View 
Avenue sand. 
MarshalUown Clay. 
The bed here identified is from 15 feet to 43 feet thick 
and extends from 200 feet from Bay View avenue to near 
Hiltons station. It represents part of the Hazlet sand of 
Clark and would correspond to the (Clay marl 4) Marshall- 
town bed of Knapp. It is a dark colored clay which varies 
in color from black to a light grey, when it has a silvery 
or micaceous appearance. Examined under the microscope 
it is found to be composed largely of clay and quartz 
grains, and some mica flakes. It is finer grained, darker in 
color and very different from the beds, one above, and the 
other below it, for they are arenaceous (silic arenites) and 
composed largely of quartz grains, while this bed is more 
of a clay or clay marl. It might be suitable for making 
brick or certain grades of earthenware. It is finer grained 
than the Navesink which rests above it in part of the sec- 
tion, but, in the rest of the section, the bed called Bay 
View Ave)nue sand comes in between. It contains very 
little glauconite and is generally very fine grained and con- 
tains much fine quartz and mica and a good deal of fine clay. 
Columbus Sand. 
This generally occurs at the base of the sections from 
Bay View avenue to near Hiltons. It represents the Upper 
Hazlet sand of Clark. It seems to be a part of the over- 
lying bed in certain instances and lenses (6) and (7) of 
this sand are included in the Marshalltown clay above. It 
varies in color from white to yellow and red, may even 
assume a slate color owing to the clay present in it. It 
contains interstratified layers of slate colored clay which is 
very smooth and fine grained. It is made up largely of 
quartz grains of variable size, and often highly colored. 
It contains numerous flakes of mica and many grains of 
glauconite scattered through it, some of which have been 
altered to iron compounds. Besides the color, the pieces 
of clay and the mica flakes are most characteristic. It 
varies in thickness from 5 feet to 25 feet although on ac- 
