Abstract :
Masonry facing at 31 widely scattered sites was characterised by the comparative lithometric
analysis of the linear dimensions, apparent areas and apparent proportions of random samples
of 50 exposed building blocks. Typically, block length lies between three-quarters and one
Roman foot and height from one-third to one-half of a foot. The mean proportions of blocks vary
with the type of stone and range from 1.50 to 2.54, with ‘military’ builders tending to prefer
low length:height ratios and stone that fractured in much the same way regardless of direction
relative to the bedding (i.e. isotropic, near-isotropic). The evidence suggests that the choice of
general-purpose stone and proportions by ‘military’ and ‘non-military’ builders varied over time
with changing circumstances. Both kinds of builder seem to have been least selective in the late
fi rst and early second centuries A.D. and again in the late third and early fourth centuries.
