**3. Results**

The analysis of the pieces of evidence and documents currently available for the area, although not reported in any classical source, testifies to the Roman frequentation of the SE territory of Ceggia.

In addition to the well-known *Via Annia* (Figure 2b) and its Roman bridge (Figure 2b.A) [58] crossing a waterway active at Roman age, in the area have been discovered the remains of an apparent rural settlement, with some wall structures and a pit along the left side of the Canalat water channel (Figure 2b.B) [10], about 800 m NW to the Roman bridge. The archaeological field survey also made it possible to collect new data useful for a better knowledge of the area, never before analyzed by similar archaeological research. The survey permits the localization of the remains of the Roman road and the identification of sporadic pieces of pottery in correspondence with the linear traces visible in aerial photographs, and a significant concentration of materials of archaeological interest along the Canalat (Figure 4b). These materials are pertinent to sites from the Roman Age (1st century BC–2nd century AD), several of which were continuously used up to the Late Antiquity (IV/V AD). In some cases, it testified to the presence of Renaissance pottery (14th–16th centuries AD), while no evidence of the medieval period was registered. All the new sites identified by the survey are located near the Canalat (Figure 4b), i.e., the watercourse that crossed the study area in Roman times and that, in correspondence with the *Via Annia*, flowed under the *Annia* bridge. Among these sites, it is worth mentioning, in particular, an apparent Roman villa along the right side of the Canalat (Figure 4b), both for the valuable materials found and for its position respect to the traces visible in the aerial photos. The site is located, in fact, on the trace of the riverbed that continues towards the Roman bridge of the *Via Annia*, probably related to a minor axis of the system of artificial lines visible from aerial photos. The multitemporal analysis of the historical frames allowed the first discrimination between traces of hydrography and modern hydraulic infrastructures, as the result of interventions carried out in the second half of the twentieth century, and others of older origin found in all the aerial photos here analyzed (Figure 3). The comparison carried out was also very useful to better outline the picture of ancient traces because some images revealed particular features not visible in others, thus contributing to the formulation of a more detailed reconstruction than that proposed by previous studies. For example, in Figure 4, there is clear evidence that a ffects the eastern sector of the study area, represented by a white band edged by two dark lines that follow its course. This is *Via Annia*, clearly identifiable in aerial photos and on the ground, due to the dispersion on the surface of pebbles and brick fragments, as well as the presence of the remains of a bridge over a waterway. Di fferent clear anomalies in the aerial photos document the ancient natural hydrography of the area, characteristic for their dark color, the morphology, and the meandering course further downstream. Their shape suggests the presence of a local drainage network probably linked to the channels in the marshes covering the area in the Middle Ages until the modern reclamation. Very similar traces of wetland palaeo-hydrography are reported about 10 km NE of Ceggia, beyond the Livenza river [1,4]. The central portion of the study area is crossed by one of this branched system of marshy canals, mixed with some artificial lines between the Piavon and Canalat channels, before the union in a single meander that seems to join the Canalat just upstream of the *Annia* Roman bridge. The artificial alignments just mentioned are also clearly recognizable in the whole area of investigation. By shape, these are not very di fferent from a Roman road, appearing as light bands between dark lines, although organized in a system. These axes, about 28 m wide, including the lateral ditches, appear as a primary grid of a hydraulic-agrarian layout, which seems to insist on the *Annia* route. In the aerial photos GAI 1954 (Table 1), it is visible that one of the WNW-ESE axes extends up to the route connecting to a military base. Among the main axes of this system, some aerial photos show the presence of dark lines, probably related to minor ditches, and other very close lines that would sugges<sup>t</sup> the existence of ancient cultivations. Furthermore, the bearing axes of the system are not entirely orthogonal to each other and delimit non-regular portions of land (e.g., the long side measures approximately 730 m, the short side 500 m). The contribution provided by the historical maps appeared fundamental to define the nature of the area, the modification over the centuries, and to limit the possible time range of the interesting anomalies visible in the aerial photos. The multi-temporal analysis of the cartography revealed, in fact, that the area was a ffected by reclamation from at least the middle of the 16th century until the end of the 19th century when an important reclamation and hydraulic-agricultural reorganization interventions profoundly transformed its asset. However, no relation appears between these recent interventions and the alignments visible in the aerial photos, placing the realization of the second ones before the presence of the marshes in the area. This evidence made by the multi-temporal analysis of the aerial photos highlights an ancient organization of the area, probably due to its hydraulic instability. The historical representations of the territory between the mid-16th and 18th centuries have also provided information on the drainage system in the area and on the interventions implemented to improve it, as well as a valuable indirect reference for the interpretation of the aerial photos. For example, the maps of the 17th and 18th centuries testify that the excavation of the straight section of Piavon is related to the burial of the same old river (today's Canalat), historically the so-called "Piavon a monito" or "Canal Morto" (Figure 5b). The comparison of these maps with a drawing of the area in 1568 (Figure 5a) dated this intervention between the end of the 16th and the beginning of the 17th century, probably during a reclamation. For our study, this information is extremely interesting because the system visible in the aerial images is crossed by the straight section of the Piavon, which suggests that it already existed at the time of the excavation of the canal (late 16th–early 17th century), also defining a timeline for the

asset of the area as well as are visible in the aerial photos. The same multitemporal analysis suggests that the watercourse in the area in Roman times probably was the Canalat, a link to the *Annia* bridge at least until the beginning of the 20th century, when the interventions slightly modified its original course (Figure 5c,d).

The resistivity map obtained from the FDEM measurements made using the CMD 1 probe (Figure 10b), referring to the ground condition recorded between the surface and the maximum depth of 1.5 m, returns a pattern perfectly consistent with the anomalies visible from aerial photo. In particular, the chromatic scale that associates blue to the most conductive areas allows immediate visualization of the two paleochannels that intercept the road and the drainage ditches in the latter. Note a greater resistivity (Figure 10b) in the central part of the map corresponding to field f.10, probably linked to the greater drainage of this field compared to the two lateral ones. The result of the electrical resistivity tomography performed at the center of field f.9 (Figure 10a,c), better defines the nature and relationship between the various anomalies. It should be noted that the ERT measurement allows us to analyze the real extension of the two paleochannels, and in particular, as witnesses that the paleochannel to the east is more extended in-depth than what can be assumed by the trace visible on the surface. Another interesting fact is the extension in depth of the most resistive area of the section on which the two arms of the road axis visible from the aerial photo are set and perfectly detected even with FDEM measurements. These data testify that the road was probably crossing an area with greater resistivity than the two nearby paleochannels, perhaps indicating not only coarser materials, but also a morphologically higher area.

**Figure 10.** Results of geophysical measurements: (**a**) localization of FDEM (yellow area) and ERT line (blue); (**b**) Map of resistivity measured from the surface to −1.5 m obtained by using FDEM; (**c**) result of ERT section.

The cores, distributed along a SW-NE section across the study site, allowed to reconstruct the stratigraphy of the deposits to a maximum depth of almost 4 m (Figure 7a). In Figure 7b are reported the stratigraphic logs of the most significant cores in terms of length of the investigated succession and/or relation with the detected archaeological features. The lithostratigraphic correlation between cores is shown in Figure 8.

The alluvial succession investigated through coring is mostly alluvial silty-clay, with only a tabular body of fine silty sand with maximum thickness of 0.8 m that extends in the central part of the section, between cores 1 and 2. The top of this sand body lies at about −3 m asl and is covered by a few-decimetres-thick layer of light olive-brown (2.5Y 5/4) silty clay with abundant pedogenetic carbonate nodules (dimensions up to 2 cm, presence 10–15%) and gray mottles that evidence the occurrence of soil formation in a probably ABk horizon (after [59]). Levels rich in carbonate nodules and mottles are also present in the underlying sand body. This buried soil is covered by 1.5–2 m of olive-brown (2.5Y 4/3) silty clay up to the surface.

At the SW and NE extremes of the section, the alluvial stratigraphy is markedly different, due to the presence of two clay lenses with maximum investigated thickness of 4 m and apparently steep sides (cores 4 and 8). These soft clays have dark gray (5Y 3/1) to greenish-gray (GLEY 6/10Y) colors and contain common fragments of reeds, wood, fresh-water mollusks, and peat layers. They are buried by a laterally-continuous light yellowish brown (2.5Y 6/3) layer of silt and clay that covers the whole investigated area. Only in correspondence of the SW end, this layer is buried by about 0.5 m of very dark grey (2.5Y 3/1) clay.

Concerning the remote sensing archaeological traces, cores 3 and 7a,b were carried out in the dark linear traces. Each core shows the presence of a silty clay sedimentary body between 0.5 (just below the plough horizon) and 1.4 m depth, grayish brown (2.5Y 5/2) color with black laminae, containing common charcoal, reworked carbonate nodules, few wood fragments and just one brick sherd of few millimeters found in core 3. One wood fragment in core 7b was 14C-dated at 384–156 BC (Table 3).

Cores 2a,b, 6, 9, and 10 were positioned between the dark linear traces, with the purpose of verifying the possible presence of anthropogenic strata related to a road. These cores show the presence of a 10–40 cm thick layer just below the surface plough horizon, consisting of compact silty clay with charcoals and fragments of terrestrial gastropods. This is the only stratigraphic evidence of the road, as below is an apparently natural and undisturbed alluvial succession.

The analysis of the exposed section, in the drainage channel of the field f.9, highlighted the presence of some interesting anomalies, just below the agricultural soil thickness of about 0.55 m. In particular, the section allowed us to identify the head of the drainage ditches on the sides of the visible remains of the bottom of the road. The total size of the road is about 28 m to 29 m, including the lateral drainage ditches with a variable size from about 2.8 m to 4.0 m. No evidence has been registered about the bottom of the drainage ditches as well as about the paleochannel, because of their depth, identified respectively by the sample cores at 1.35 m and 1.5 m below the surface. More in general, no structural materials (e.g., stones, wood, etc.) were identified in the section, excepting some, not relevant, small brick fragments. It should be noted that an extensive yellow clayey-loamy level, probably an alluvial deposit, of about 0.2 m in thickness (US 101 in Figure 9c) was detected. Apparently, this represents the bottom of the linear structures visible in the aerial photos, where the upper part of these structures has been probably cut by agricultural modern cultivation practices. The yellow clayey-loamy level (US 101 in Figure 9c) also covers the big paleochannel. In this position, the US 101 is deeper than in other parts of the section (0.7 m below the surface), and is covered by a grey clayey-loamy layer (US 109 in Figure 9c), of about 0.2 m of thickness, probably related to a swamping phase of the area (Figure 9c—section I) and here preserved because of its depth.
