We present a single epoch of high signal-to-noise ratio spectropolarimetry of the Type Ia supernova ( SN Ia ) 2004S taken nine days after maximum light .
The flux spectrum is normal , but with the additional presence of high-velocity ( HV ) line features in both Ca ii and Fe ii .
The object shows continuum polarization at the 0.4 % level in the red , a value which appears to be typical of SNe Ia .
The continuum data are consistent with a \sim 10 % global asphericity in an axisymmetric geometry .
Unlike previous observations of other SNe Ia with HV features , the HV features in SN 2004S show no strong polarimetric signature , though this may be due to the timing of our observations .
Instead , the object shows line polarization features ( P \leq 0.5 % ) that are rotated with respect to the axis of symmetry of the continuum .
The line features are visible in Si ii , Fe ii , and Ca ii , and appear to be narrowly confined in velocity space just above the photosphere .
These polarization features are a result of compositional inhomogeneities in the ejecta .
They may represent newly synthesized elements whose clumpy spatial distribution within the ejecta is distinct from that of the globally aspherical ejecta as a whole .