68 
FAIRBANKS AND RAMPART QUADRANGLES. 
tracted by freezing in the fall. The resulting hydrostatic pressure 
cracks the ice and the water overflows and freezes. This process is 
repeated until a considerable thickness of ice is accumulated. 
The valley is V-shaped in cross section, and the eastern slope is 
often benched, while the western is more abrupt and has remnants 
of benches at but few places. Five well-marked benches rise at irreg- 
ular intervals above the floor between Little Minook Junior Creek 
and Hoosier Creek (fig. 3), the highest of which is about 500 feet. 
These benches are features of much importance in both the physiog- 
raphy and economic geology of the region. Important gravels cover 
the highest one, which lies on the east side of the Minook and extends 
from Hunter Creek to about a mile above Florida Creek. It will be 
described later. A small remnant of the same bench is found on the 
north side of the mouth of Montana Creek and another on the north 
side of the mouth of Ruby Creek. Other remnants are found on 
the north side of the mouth of Chapman Creek and at a point about 
Fig. 3. — Diagrammatic sketch of Minook Valley. 
4^ miles above the Chapman on the same side of Minook Creek. 
The last two benches show no gravel. On the west side of the creek 
but few remnants of benches are found. One, about 50 feet high, 
extends to a little above the mouth of Hunter Creek, and is probably 
an extension of a corresponding bench on the south side of the Yukon. 
It seems probable that all of the benches of Minook Creek may be 
more or less closely correlated with the benches of the Yukon. In 
the vicinity of the mouth of Slate Creek is a bench cut in the 
upturned slates and thin-bedded quartzites to a depth of 12 to 16 feet 
and covered by 4 or 5 feet of gravel and a foot or more of muck. No 
gravel has yet been found upon the benches of intermediate height, 
but further investigation may show its presence. 
In its upper course the creek flows somewhat north of east for about 
2 miles, and here the topography of its valley is altogether differ- 
ent from that of the lower part. The north side is a long, gentle 
slope with a greater rise in the upper part, while the south side is 
steep and the stream Aoavs near its base. The asymmetry of this part 
of the valley is repeated in Eureka, Pioneer, Hutlina, Omega, New 
