Bulletin 23. Potash in the Greensands of NJ, 1923 - State of New ...

20 POTASH IN TttE GREENS&IWDS OF NRW JEILSEY.
drying. ]'he average weight of the five dried samples was about 80
pounds to the cubic foot, or 2,160 pounds to the cubic yard.
The figures given above are probably fairly accurate for the weight
of the better material as ordinarily handled. Estimates of tonnage,
however, are concerned with marl in the ground, which is presumably
much more compact than mar] removed to stock piles. According
to the density determinations given in the table the weight of dry
greensand, if massive and compact, would range from 182.7 to 191.4
pounds to the cubic foot and would average about 186 pounds to
the cubic foot, or more than 5,000 pounds to the cubic yard. The
marl in the ground, being unconsolidated, is probably much less
compact than the degree required by this figure. Its actual weight
doubtless lies between the two extremes given and for the purposes
of estimate may be assumed to be their mean, 133 pounds to the cubic
foot or about 3,580 pounds to the cubic yard. The voids, or open
spaces due to lack of consolidation, would represent on this asspmption
28 per cent of the mass of the marl.
Collection of well data.--During the progress of field work several
well drillers were interviewed and farms on which wells had been sunk
were visited. The well records at the office of the State geologist
at Trenton were searched for data bearing on the districts explored.
Published accounts were also reviewed with the hope of extending
_he inferences based on the drilling.
Otherfield data.--The field notes of the State geologist and his staff
were kindly placed at the disposal of the writer and have been utilized
to supplement the information gained by drilling.
GEOLOGIC MA] _.
The geologic map as prepared by Knapp on the scale of 1 inch to
the mile (1:63,360) has been adjusted to the somewhat larger base
of the U. S. Geological Survey (1:62,500). (See Pls. I-III.) The
map does not show Quaternary deposits, and as these are widely
distributed throughout the area, it shows the actual anrfaco conditions
at comparatively few places. It is valuable, however, in showing the
general breadth and outline of the areas in which the marl beds may be
presumed to be within reach of the surface and may serve as a useful
basis for tonnage estimates for any selected area. In its preparation
Kmapp visited all available exposures and made frequent tests with
the auger. The map may be regarded as generally accurate. One
or two slight modifications in it have been made as a result of the
writer's observations. At a few other places surface examination
suggested further modifications; but without opportunity for the
detailed work necessary for revision it was thought best to leave the
map unchanged. It is therefore presented essentially as drawn by
Knapp but without delineation of the formations preceding the Navesink
or succeeding the Shark River.
NEW JERSEY GEOLOGICAL SURVEY