CIPA 2003 XIX th International Symposium, 30 September - 04 October, 2003, Antalya, Turkey 
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soil, rendered the identification of the useful signals more 
difficult. In general the anomalies have a curved or linear trend 
which in some cases is clearly referable to ruins of various 
houses. The archaeologists lingered over the elongated anomaly 
detected close to the theatre in the THR area. It is a rectilinear 
signal about 60 meters long, which appears moreover parallel to 
a defense wall of the IV century A.D.. The anomaly is nearly 5 
meters large and its positive and negative values respectively 
range around ±8 nT (Figure 3a). 
Figure 3. a) Magnetogram of the THR area. The AB anomaly 
extends for about 60 meters. Inside the white square area, an 
excavation was undertaken, b) e c) The recovered structures. 
In the summer of 1999 a first excavation was performed in 
correspondence of this signal and a double-columned marble 
column was found at a depth of about 0.8 m (Figure 3b). The 
extension of the trench along the direction of the anomaly 
proved to be fruitless. Only when the excavation was widened 
laterally and dug deeper (1.1 m) a pavement made of blocks of 
grainstone (0.6X1.3X0.12 m) was discovered. The 
archaeologists had considered it as a basement of a long 
colonnade or of a portico. At present more then 50 meters of 
this structure has been recovered (Figure 3c). 
Once having been mapped the basement showed a good 
correspondence in its relative position respect to the AB 
anomaly. 
3.2 Canosa (Italy) 
As it emerges from a rich tradition of studies Canusium 
(Canosa) had, between the IV and VI century A.D., a leading 
role inside the provinces of Apulia et Calabria and in general in 
all of southern Italy. It represented the political and 
administrative center being the seat both of the provincial 
governor and of the concilium of the Apuli et Calabri. Under the 
economic profile of notable importance were the agricultural 
activities, the transhumant breeding and handicraft productions. 
In Canusium moreover there was a prestigious diocese ruled by 
bishops often involved in important councils and in delicate 
diplomatic operations (Volpe et al., 2002). 
Historical sources and some recoveries on the ground have 
suggested the presence of an episcopal complex of early 
Christian age (IV-VI A.D.) in the outskirts of Canosa, on the 
hill of S.Pietro. In the summer 2001, within a research project 
with the University of Foggia (Italy), a high resolution 
magnetic investigation was carried out. 
Figure 4. Magnetogram of the whole surveyed area. 
The purpose of the survey was the location and the 
identification of the principal buried structures so to delimit the 
area with the greatest archaeological potentialities, optimizing 
in this way the excavations with a noticeable saving of time and 
money. 
Altogether 3450 m 2 were surveyed. In Figure 4 the whole 
magnetogram is represented. A greater concentration of 
meaningful signals is immediately noted within a central zone 
delimited by the white contour. Many linear and curved 
anomalies are well recognizable. These are mostly negative 
with values that are around —10 nT. The minimum and 
maximum values of the entire area are much greater (-583 nT, 
1986 nT) and connected to the intense signal formed by the 
regular oblique sequence of white spots absorbed in a 
continuous black halo. This strong superficial noise cuts 
sideways the whole magnetogram overlapping the weaker 
anomalies produced by the archaeological remains. Actually the 
following excavations highlighted a set of metallic anchorages, 
rests of a vineyard uprooted in the recent past. 
In Figure 5a the most significant anomalies were outlined 
schematically illustrating in this way the possible shape of the 
correspondent sources. The archaeologists used this drawing to 
Figure 5. a) All the highlighted anomalies in the magnetogram 
are sketched with white lines in order to show the possible 
shape of the sources, b) Aerial photo of the episcopal complex 
revealed in the S.Pietro Hill.. 
plan their field work. Figure 5b shows the aerial photo of the 
excavations, taken from a captive balloon: all the recovered 
structures are well visible. They are generally made of 
calcareous stones. Comparing the photo with the magnetogram 
it can be noticed how all the magnetic features underlined inside 
the dug area had a satisfactory archaeological feedback. 
However, it is also true that many structures which are not 
identifiable in the magnetogram exist. This is mainly due to the 
complexity of the sources. In fact as shown in the aerial photo,