  The results of ac and dc magnetization and heat capacity measurements on the
oxides, Ca$_3$Co$_{1+x}$Mn$_{1-x}$O$_6$, forming in a K$_4$CdCl$_6$-derived
rhombohedral quasi-one-dimensional crystal structure, are reported. As far as
Ca$_3$Co$_2$O$_6$ is concerned, the results reveal truly complex nature of the
two magnetic transitions, identified to set in at 24 and 12 K in the previous
literature. However, partial replacement of Co by Mn apparently results in a
long magnetic ordering of an antiferromagnetic type (below 13 and 18 K for x=
0.0 and 0.25 respectively), instead of spin-glass freezing in spite of the fact
that there is Co-Mn disorder; in addition, interestingly there are hysteretic
spin reorientation effects as revealed by isothermal magnetization behavior.
