  We report a study of magnetic susceptibility and electrical resistivity as a
function of temperature and magnetic field in superconducting crystals of
La$_{2-x}$Ca$_{1+x}$Cu$_{2}$O$_{6}$ with $x=0.10$ and 0.15 and transition
temperature $T_{c}^{\rm m} = 54$ K (determined from the susceptibility). When
an external magnetic field is applied perpendicular to the CuO$_2$ bilayers,
the resistive superconducting transition measured with currents flowing
perpendicular to the bilayers is substantially lower than that found with
currents flowing parallel to the bilayers. Intriguingly, this anisotropic
behavior is quite similar to that observed for the magnetic irreversibility
points with the field applied either perpendicular or parallel to the bilayers.
We discuss the results in the context of other studies that have found evidence
for the decoupling of superconducting layers induced by a perpendicular
magnetic field.
