  High-velocity features in Type Ia supernova spectra provide a way to probe
the outer layers of these explosions. The maximum-light spectra of the unique
Type Ia supernova 2000cx exhibit interesting Ca II features with high-velocity
components. The infrared triplet absorption is quadruply notched, while the H&K
absorption is wide and flat. Stimulated by a three-dimensional interpretation
of similar Ca II features in another Type Ia supernova (SN 2001el, Kasen et al.
2003), we present alternative spherically symmetric and three-dimensional
ejecta models to fit the high-velocity (v > 16,000 km/s) Ca II features of SN
2000cx. We also present simple estimates of the high-velocity ejecta mass for a
few trial compositions and discuss their implications for explosion modelling.
