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Gibbons, F. R. (1961). Some misconceptions about what soil surveys can do. Journal of Soil 
Science Vol. 12. No. I. 
Binnie, Deacon and Gourlay (1956). Report to the Govt, of Iraq Development Board on the 
Nahrwan, Adheim and Ishaqui areas, vol ii. 
Belcher, D. J. (1959). Microforms and Features. Photogrammetric Engineering 25. 
Soil Survey Staff (1960). Soil Survey of Great Britain Field Handbook. 
Discussion 
Dr. R. Smith (Ireland) commented that the range variation usually allowed in such profile 
characteristics as colour, texture, structure, pH, salinity etc. should be broadened over that 
usually allowed for soil series, so that such surface features as e.g. gilgai patterns and drainage 
characteristics will embrace one cartographic soil series. Although this is a very controversial 
matter he would give his support to Mr. Curtis’ suggestion. 
Mr. G. Koechley (U.S.A.) believed that we do not sufficiently distinguish between the 
application of photo interpretation to small scale surveys and that to highly detailed ones at 
1 : 20,000 scale or larger. Photo interpretation is an excellent and useful tool, but one re 
quiring a great deal more field checking for the more complex soil surveys. 
Dr. R. Maignien (France) remarked that it is very dangerous to define the soil units only 
according to those superficial aspects which can be seen from the aerial photographs. It is 
necessary to multiply the studies on the correlation between the soils observed in the field and 
the phenomena which can be observed from the photographs. Intensive studies have revealed 
that this correlation was weak on the series level, but this was only the case for one particular 
region. Mr. Curtis agreed that soil profile characteristics must remain the basis for much of 
our thinking about soils. However, his view is that soil mapping units can and should be 
defined in terms of landscape features. Soil surveyors and interpreters should cooperate in 
producing suitable classifications. 
Dr. A. P. A. Vink (W.G. chairman) concluded that in the future a more careful distinction 
between the units of taxonomic classification, such as used in the Soil Classification (7th 
approximation), and those of cartographic classification as used in our mapping units, will 
be necessary. He stressed the need for a better appraisal of both kinds of classification.