  We have studied the temperature dependence of conductivity, $\sigma(T)$, in
two series of Ag$_{x}$(SnO$_2$)$_{1-x}$ and Mo$_{x}$(SnO$_2$)$_{1-x}$ granular
films lying below the percolation threshold, where $x$ is the metal volume
fraction. The metal grains in the former series have approximately spherical
shape, whereas in the latter series contain numerous small substructures. In
both series of films, we have observed the $\sigma \propto \exp[-(T_0/T)^m]$
temperature dependence, with $m\,\simeq\,1/2$, over the wide $T$ range from 2
to 80 (100) K, where $T_0$ is a characteristic temperature. Our $\sigma$($T$)
results are explained in term of the Abeles-Sheng model which considers the
structural effect of metal grains. The extracted values of the optimal
separation between grains ($s_{m}$) and the charging energy ($E_{c}$) slightly
increase with decreasing $x$. The variation of the parameter $C(x)$, defined in
the Abeles-Sheng model, is in consistency with a simplified expression which
depends only on $x$ and the dielectric constant of the insulating matrix. As
the temperature is increased to above $\sim$\,100 K, a crossover to the
thermally fluctuation-induced tunneling conduction processes is observed.
