AGGREGATE POTENTIAL
HIGH AGGREGATE POTENTIAL:  the relative probability of an aggregate deposit
existing within this area is high.  The percentage of shale is low, percentage
of gravel is high, deposit size varies, and overburden thickness varies.  This
map unit includes geologic units B-1, O-1, O-3, O-4, and So.

MODERATE AGGREGATE POTENTIAL:  the relative probability of an aggregate deposit
existing within this area is moderate.  The percentage of shale is low, percentage
of gravel varies, deposit size is generally smaller, and overburden thickness is
thicker.  This map unit includes geologic units B-2 and I-1.

SLIGHT AGGREGATE POTENTIAL:  the relative probability of an aggregate deposit
existing within this area is slight.  The percentage of shale is higher, the
percentage of gravel varies, the deposit size is smaller, and overburden is 
thicker.  This map unit includes geologic units B-3, O-2, and I-2.

LIMITED AGGREGATE POTENTIAL:  the relative probability of an aggregate deposit
existing within this area is limited.  This map unit includes areas of silt
deposited in Glacial Lake Agassiz and glacial till.


GRAVEL PITS (symbolized by an areal symbol)
GRAVEL PIT:  area of pit delineated from interpretation of aerial photographs.


GRAVEL PITS (symbolized by a point symbol)
GRAVEL PIT:  pit identified by field work.  Area of pit not delineated because
the pit was not visible on the aerial photographs.

GRAVEL PIT:  pit identified on 1:24000 USGS topographic maps and not a part
of pits delineated from interpretation of aerial photographs.


