  We report the first observation of two narrow charmed strange baryons
decaying to $\Xi_c^+\gamma$ and $\Xi_c^0\gamma$, respectively, using data from
the CLEO II detector at CESR. We interpret the observed signals as the
$\Xi_c^{+\prime}(c{su})$ and $\Xi_c^{0\prime}(c{sd})$, the symmetric partners
of the well-established antisymmetric $\Xi_c^+(c[su])$ and $\Xi_c^0(c[sd])$.
The mass differences $M(\Xi_c^{+\prime})-M(\Xi_c^+)$ and
$M(\Xi_c^{0\prime})-M(\Xi_c^0)$ are measured to be $107.8\pm 1.7\pm 2.5$ and
$107.0\pm 1.4\pm 2.5 MeV/c^2$, respectively.
