A. Drawingof a roadcut exposure, copied from a page of a field notebook of A. H.
Sylvester, and reduced approximately 30%. Note that the Quaternary terrace sediments
(Qt) are displaced along the most recently active fault trace, and that older traces cut
Neogene sediments and are truncated by the erosion surface beneath the Qt. B. Outline of
the outcrop of A, showing measurements (arrows) that could be used to lay out the main
lines of a field drawing. C. Rectangular grid used as a basis for a drawing (here a very
large-scale map) of a horizontal outcrop surface (ux unexposed).