  We investigate the formation of molecular clouds from atomic gas by using
three-dimensional magnetohydrodynamical simulations,including non-equilibrium
chemical reactions, heating/cooling processes, and self-gravity by changing the
collision speed $V_0$ and the angle $\theta$ between the magnetic field and
colliding flow. We found that the efficiency of the dense gas formation depends
on $\theta$. For small $\theta$, anisotropic super-Alfv\'enic turbulence delays
the formation of gravitationally unstable clumps. An increase in $\theta$
develops shock-amplified magnetic fields along which the gas is accumulated,
making prominent filamentary structures. We further investigate the statistical
properties of dense clumps identified with different density thresholds. The
statistical properties of the dense clumps with lower densities depend on $V_0$
and $\theta$ because their properties are inherited from the global turbulence
structure of the molecular clouds. By contrast, denser clumps appear to have
asymptotic universal statistical properties, which do not depend on the
properties of the colliding flow significantly. The internal velocity
dispersions approach subsonic and plasma $\beta$ becomes order of unity. We
develop an analytic formula of the virial parameter which reproduces the
simulation results reasonably well. This property may be one of the reasons for
the universality of the initial mass function of stars.
