The hopping conductivity in a disordered system which is composed of small
(semi-) metallic granules is presented. Due to the irregular shape of each
granule, the level statistics of a free electron in a granule is expressed
by a random matrix, and a formula for the temperature-dependent conductivit
y (TDC) is obtained for such a disordered system. This TDC shows an apparen
t metal-insulator transition and is in good agreement with experimental res
ults for disordered carbons.