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SYMPOSIUM PHOTO INTERPRETATION, DELFT 1962 
monly designated “Muskeg” in Canada, peatland in Great Britain and by 
other expressions in Scandinavia, U.S.S.R., Latin America, etc. 
In Canada, Organic Terrain covers well over 500,000 square miles of sur 
face. To know what this terrain is, how it varies, and how it can be assessed 
for any or all purposes, has become nationally expedient. The task is not easy 
for various reasons. An important one is that overland access involving such 
a vast expanse is not only difficult, or sometimes almost impossible, but is also 
expensive. 
Recent research [8] has encouraged a view that this difficulty can be sub 
stantially circumvented if adequate evaluation of the terrain properties can 
be achieved either by direct observation from the air or by inspection of air- 
photos, or both. There are two basic assumptions that obtain for this possibil 
ity. One is that objective aerial inspection will reveal the presence of patterns 
which symbolize inherent characteristics of the terrain; the other is that such 
patterns, if they exist, can be interpreted in engineering terms. 
The writer and his associates have shown that in organic terrain, the fossil 
ized component, peat, reveals botanical trends that culminate in production 
of specified living cover, the contemporary component of the terrain [2, 4, 6]. 
Where fossil trends differ, vegetal cover differs accordingly. By reference to 
differentials in cover, therefore, one affords indirect reference to sub-surface 
botanical trends in historical retrospect and to differentials in these trends. 
Now these trends being botanical are subject to characteristic constitutional 
limitation and this is manifested in peat structure. Structural difference, or 
ganized as to constitutional differentials, is therefore observable in peat. 
Phenomena under cosmic influence are classifiable if they recur as do specific 
differences in peat. Once recognized by interpretive procedure, they may be 
interpreted elsewhere. By reason of the relationship between cover and peat, 
it follows that vegetal cover is the significant key to detection of either sub 
surface structural condition or structural differentials. 
It is perhaps not surprising in view of the argument presented that vegetal 
cover of a given type will show distributional delineation. Thus surficial pat 
terns arise which characterize organic sub-surface. Such patterns are observ 
able, of course, from the air, and they recur. Thus the sub-surface botanical 
and structural constitution can be interpreted directly or indirectly from the 
air. 
The most frequently recurring patterns observable at an altitude of 30,000 ft 
are known [3] and have been named as shown in the legends to the photo 
graphs which represent them, figs. 1, 2, 3, 4, 5. 
Though structural composition in the peat and the resulting air-form pattern 
are functions of botanical trend, there are factors other than biotic that contri 
bute to pattern. These may arise through the influence of the mineral sub 
layer, ice, the accumulative effect of organic deposition, or water [7]. They 
are secondarily imposed after biotic relations are established and the peat 
formation has commenced. The aspects of relationship between the primary 
(botanical) and secondary (extra-biotic) factors have not been examined and