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pattern which matches the underlying ridge orientation. 
In FIGURE 3, the letter "A" indicates an example of a well 
defined landslide crater. The debris has been washed away by 
the river, but the crater shows the typical ridge pattern. The 
troughs hold some water and the ridges are accented by the 
overgrowing tree pattern. 
Both large gullies shown in this stereo - pair have banks 
formed by numerous landslides and sloughing. The gully indicated 
by "B" is the more active. The lighter tone "shadow" around 
several branches of this gully indicates water infiltration 
which can lead to seepage and landsliding. The numerous white 
flecks on this gully's slopes are a sloughing phenomenon which 
is a precursor to more serious earth movement. 
Confusion of landslides with other features, is quite possible. 
The ridge pattern of debris in the landslide crater may be 
contour ploughing or a reforestration pattern. The crater itself, 
may be mistaken as a borrow pit, or a sand blowout. Experience 
and thorough observation is necessary to be accurate. 
Although the complete inventory for eastern Ontario cannot 
be reproduced here due to space limitations, a sample area is 
shown in FIGURE 4 at a scale of 1:50,000. This figure represents 
one of the areas of great landslide incidence, and is a portion 
of N.T.S. map 31 G/ll - Thurso East. The craters of all recog 
nizable landslides are outlined. 
LANDSLIDE SUSCEPTIBILITY 
To determine landslide susceptibility of an area, very 
recent imagery is required. The imagery should be false colour 
infrared, or normal colour, because tone analysis must now be 
added to pattern recognition. Generally speaking, the higher and 
steeper a clay slope, the better chance for landsliding. Outside 
of this basic requirement, other landslide - aggravating features 
must be searched for: toe erosion, sloughing, lack of vegetative 
cover on a slope, extra weight on the bank, etc. 
Where tone analysis is important is in determining the 
nature of the moisture regime of the soil. Seepage on the slope 
face, excessive water in or on top of the bank, piping in sand 
are some of the water - oriented observables. Since false colour 
infrared film is greatly altered in hue depending on the moisture 
content of the soil, (or the vigour of the overgrowing vegetation 
which indicates soil moisture status) it is ideal to use it for