  We present the preliminary results of a survey that makes use of several deep
exposures obtained with the X-Ray telescopes of the BeppoSAX satellite. The
survey limiting sensitivity is 5 x 10^-14 cgs in the 2-10 keV band and 7 x
10^-14 cgs in the harder 5-10 keV band. We find that the 2-10 keV LogN-LogS is
consistent with that determined in ASCA surveys. The counts in the 5-10 keV
band imply either a very hard average spectral slope or the existence of a
population of heavily absorbed sources that can hardly be detected in soft
X-ray surveys. A sample of 83 serendipitous sources has been compiled from a
systematic search in 50 MECS images. The analysis of the hardness ratio of this
sample also implies very hard or heavily cutoff spectral shapes.
