the following catalogue includes the major monuments from Rome and environs discussed in this study. The purpose of the catalogue is threefold. First, each entry introduces the location, date, purpose, and, if relevant, the later history of the monument. Second, the details of the various constructional issues relevant to this study are summarized together. If the issue is discussed at length in the main text, a cross reference is provided rather than repeat the information. In cases where the observations are my own unpublished on-site observations, I include more details than if the information is published elsewhere. Third, the relevant bibliography that deals with the construction techniques used in the monument is included at the end of each entry. I also cite the references from the Lexicon Topographicum urbis Romae (LTUR), which the reader can consult for a more comprehensive bibliography. Each monument is located on Map 1 (p. 4) according to its catalogue number.

PONS FABRICIUS (62 b.c.)

COMMENTS: The Pons Fabricius consists of two arches (24.5-m span) and connects the left bank of the Tiber to Tiber Island. Identical inscriptions on both sides of one of the arches indicate that it was built by L. Fabricus in 62 b.c.

Materials. The arches, approximately 6 m thick, are built of peperino (lapis Gabinus) blocks with an outer facing of travertine voussoirs.

Centering. The arch connecting to the left bank has two cuttings, spaced approximately 4.5 m apart, along the impost at either side of the intrados.