The reasons are many: first, the tool is an object of daily use, subjected while in service to hard wear and, in some cases, ultimate destruction; second, a tool's usefulness is apt to continue through many years and through the hands of several generations of craftsmen, with the result that its origins become lost; third, the achievement of an implement of demonstrated proficiency dictated against radical, and therefore easily datable, changes in shape or style; and fourth, dated survivals needed to establish a range of firm control specimens for the better identification of unknowns, particularly the wooden elements of tools-handles, moldings, and plane bodies-are frustratingly few in non-arid archaeological sites.
"Woodworking Tools 1600-1900"
Peter C. Welsh
The great cities of the Mesopotamian plains show faint traces of town-planning datable to the eighth and following centuries, of which the Greeks seem to have heard and which they may have copied.
"Ancient Town-Planning"
F. Haverfield
The statistics of datable objects discovered in these buildings seem conclusive on this point.
"The Romanization of Roman Britain"
F. Haverfield