Unit H3. Unit H3 is bounded below by S3 and above by the modern lagoon floor, and shows marked thickness changes from c. 1 to 14 m, particularly toward the Malamocco Inlet (Figures 5 and 6). The unit is usually truncated by the modern tidal channels, although it is locally found within the larger ones (Figure 5a and b). Like the underlying units, Unit H3 contains high- to low-amplitude reflectors that are oblique or U-shaped in the intervals characterized by the concave-up features of S3, and near parallel to S3 in the flatter tracts (Figures 5 and 6). In some cases, near horizontal reflectors mantle those inclined (Figures 5a and 6a and b). A composite pattern of oblique and U-shaped reflectors, similar to those found in the larger concave-up features characterizing Unit H1, is present in the southern part of the SH312 seismic profile, near the Malamocco Inlet (Figure 5b). In that location, the inclined reflectors of Unit H3 almost reach the lagoon floor (Figure 5b).