The above-noted developments in the 1950s and 1960s in Moine geology show the growing recognition of the importance of combining lithological mapping with shrewd and careful observations in the field of folds, lineations and schistosities in order to unravel the geometrical history of deformed rocks. The increase in the field data collected, dips and strikes of bedding, cleavage or schistosity and the axial planes of folds, plunge amounts and geographical directions of folds and lineations (Fig. 11.1) led to an explosion of data and the neéd to be able to manipulate, display and synthesize such data at a time before computers were generally available (Howarth 1999). The process was enormously facilitated by the gradual extension of the use of the stereographic projection from crystallography (in which, as has been seen, upper hemisphere plotting is used), to structural geology (in which lower hemisphere plotting is conventional, presumably because folds and lineations are normally considered in their down-plunge attitudes, not the reverse).
There is no doubt that the widespread use of the stereogram in structural geology in Britain was promoted, more than any other factor (Sutton 1960b), by the publication of Phillips’ (1954b) textbook The Use of Stereographic Projection in Structural Geology, following his return from Australia. In the preface, Phillips paid tribute to the usefulness of Cotton & Garretty's (1945) report.268 Phillips’ chapter entitled ‘Tectonic synthesis in stereographic (and related) projection’, illustrated how the Lambert equal-area projection (Fig. 4.4) could be applied to summarize the orientation of joints, lineation and planes of schistosity, using examples from the schists of Start Point, Devon (Fig. 11.2) and the Moine schists.