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The Saint Jean Vianney landslide has redirected attention to soil studies conducted in 1941, as part of the site investigation program for the adjacent wartime Shipshaw power project. These included early studies of Leda clay, the sensitivity of which was recognized but not fully appreciated nor understood. Buried organic matter was encountered at one dam site. The possibility of landslide action accounting for the unusual position of this material was discounted in 1941. Recent studies by LaSalle have demonstrated the existence of a massive ancient landslide adjacent to the Shipshaw site. Earth movement resulting from this old landslide could explain the organic stratum. Carbon-14 dating suggests a date for this massive landslide that agrees with historical records of the great Quebec earthquake of August 1663. This caused earth movements of a magnitude not seen in Canada since that time, confirming the possibility of these being the explanation of the unusual position of the organic deposits. References to two papers on the Shipshaw studies, published in 1945, are given. Important corrections to conclusions contained in these papers are suggested.

Geology is of fundamental importance as far as the planning of physical facilities and individual structure is concerned and recognition of this allows wise use of urban and rural land. As land is the surface expression of the underlying geology, planning should not proceed without fully appreciating geological conditions. Foundation, tunnels, transportation routes, etc. depend for their stability and performance on the geological setting.There are, however, three aspects of geology related to areal planning which are not quite so obvious. First, prior to land being developed it is desirable to know if any useful materials can be retrieved from it before construction starts. Sequential land planning is therefore important. Secondly, there is likely to be an increased utilization of underground space in the years ahead. Thirdly, all those concerned with planning must realise that groundwater is a dynamic system and that, in particular, watertables can rise and fall, and thereby can influence subsurface structures.

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