Mr. Holmes seems to have missed the point of this paper by implying in his letter that the resistivity results were interpreted without reference to the available geological information, but based only upon the preliminary borehole information.
The main reason for the publication of this particular case history was the availability of information from holes drilled both before and after the resistivity survey. This enabled the advantages and limitations of the methods to be assessed for this particular site.
In the introduction a simple geological section based upon three boreholes was drawn to show how such sections are unfortunately drawn up from borehole information, with little reference to available geological information. The author, well aware of the varied lithology of the area, carried out the resistivity survey to prove and possibly define this variability.
The remarks of Mr. Holmes concerning the importance of careful literature study at an early stage of site investigation are, however, heartily endorsed.