  The temperature and angular dependencies of the resistive upper critical
magnetic field $B_{c2}$ reveal a dimensional crossover of the superconducting
state in the highly anisotropic misfit-layer single crystal of
(LaSe)$_{1.14}$(NbSe$_2$) with the critical temperature $T_c$ of 1.23 K. The
temperature dependence of the upper critical field $B_{c2\parallel ab}(T)$ for
a field orientation along the conducting $(ab)$-planes displays a
characteristic upturn at 1.1 K and below this temperature the angular
dependence of $B_{c2}$ has a cusp around the parallel field orientation. Both
these typical features are observed for the first time in a naturally
crystalline layered system.
