vertical relief found in the field and recognizable 
in aerial photographs. These are outlined as 
follows: 
Soils Map 
Unit No. 
ile High-center polygons covering two- 
thirds or more of the ground sur- 
face; center-trough contrast, 
0.5-1 m. 
2, High-center polygons covering two- 
thirds or more of the ground sur- 
face; center-trough contrast, 0.5 m 
or less. 
Terrain-Relief Type 
3: Low-center polygons covering two- 
thirds or more of the ground sur- 
face; center-rim contrast, 0.5-1 m. 
4. Low-center polygons covering two- 
thirds or more of the ground sur- 
face; center-rim contrast, 0.5 m or 
less. 
5, Transitional features; mixed high- 
and low-center polygons with neith- 
er exceeding three-quarters of the 
area, or low-center polygons in 
which the trough depth greatly 
exceeds the rim-center contrast. 
6. Steep, eroding (collapsing) stream 
or pond margin banks. 
7. Polygonal ground surface pattern. 
Polygons are neither high- nor low- 
center; relief contrast, 15 cm. 
8. Hummocky ground, either in the 
form of rounded hummocks 30 cm 
or more in height, or flat-topped 
polygonal hummocks 30 to 50 cm 
in diameter and 30 cm or less in 
height. 
9. Aligned, discontinuous hummock 
ridges. 
10. No apparent ground surface 
pattern. 
In an effort to place the terrain-relief classes 
in a regional context, they are combined with 
slope classes on Plate |; 0 to 2%; > 2 to 6%, and 
> 6%. 
on] 
oO 
Principal soil types recognized on Plate | 
Five distinct soil types have been recognized 
within the area covered by Plate |, and at least 
two others occur beyond its limits. 
As a general rule, the region’s soils are 
shallow; the mean August thaw depth is approxi- 
mately 43 cm, with a range between 25 and 60 
cm. The soils are mostly at or near saturation 
throughout much of the thaw period. Moisture 
contents range from less than 100% (on a weight 
basis) for those soils on the more elevated 
and/or better drained topographic positions to 
as much as 400% on the lower and/or more 
poorly drained sites. An August mean value of 
225% is probably reasonable for the map area. 
With the exception of active frost medallions 
and some other mineral soil areas, the majority 
of soils have a surface horizon composed of a 
variable thickness of fibrous, peaty organic 
materials. The surface horizon may be underlain 
by one or more mineral horizons which com- 
monly contain wide-ranging amounts of organic 
materials. Although the great majority of the 
soils have a peaty (organic) surface horizon, few 
qualify as organic soils (Histosols) under present 
definitions of the National Soil Taxonomy (Soil 
Survey Staff, in press). Most fall within the defini- 
tions of a mineral soil order composed of soils 
showing, in this area, relatively weak horizon 
development. Names at the suborder level are 
indicative of soil wetness. They are prefaced at 
still lower orders of classification by the letters 
(Cry), reflecting the cold soil temperatures. 
Finally, one or more qualifying terms may 
precede the soil name which indicate the 
presence of a significant organic horizon at the 
surface (histic), or the fact the soils contain 
permafrost and may be subjected to some form of 
frost disturbance (pergelic). A soil classification 
scheme proposed by Tedrow et al. (1958) and 
commonly employed by arctic tundra ecologists 
is presented for correlation. 
Each of the distinct soil types encountered 
in the map area is given a numerical designa- 
tion. On the soils map, the soil-type number 
designations, in a combination of one to three 
digits, precede the terrain-relief number designa- 
tion. The map symbol is completed by the 
addition of a number designation indicative of 
the regional slope angle. The last digit indicates 
