The use of dressed stone rather than gravel as a surface dressing was occasionally held to be a sign against Roman construction's causeway: the majority of Roman roads that were finished with a material other than simply packed earth were dressed in either packed gravel or pebbles. There are other examples of Roman roads paved with stone blocks, including the section of the Via Appia—the oldest major Roman route in Italy—near Albano. Historians Richard A Gabriel and Michael Grant state that of the of known Roman roads, over may have been stone-paved. The Roman writer Ulpian specifically differentiates between "via munita", which always had a paved stone surface, and "via glareata", which were earthed roads with either gravelled surfaces or a gravelled subsurface and paving on top. The causeway may well have had a gravel surface dressing originally, which has been removed since robbing and natural weathering. Another difference in construction detail between Wade's Causeway and a typical Roman road is its lack of a foundation of large stones. Codrington and archaeologist John Ward stress that the structure of Roman roads varied greatly depending upon their situation and the materials available, especially within Britain.