  Extended air showers originate from interactions between ultra-high-energy
cosmic rays and nuclei in the Earth's atmosphere. At present there are some
discrepancies between experimental observed properties of these air showers and
theoretical predictions obtained by using standard hadronic interaction models
for cosmic ray primaries with laboratory energies above 10^5 - 10^6 TeV. In
this contribution, we will present a preliminary discussion of the possibility
(in the framework of TeV gravity models) that shower development may begin with
the production of a microscopic black hole (MBH) at the moment of the primary
collision, which then evaporates and decays, by emitting gravitons and Standard
Model quanta. From our preliminary investigations it appears that lepton
distributions are more likely to reveal the presence of a MBH than photon
distributions.
