  We analyze a high-resolution, high signal-to-noise spectrum of the
carbon-rich, extremely metal-poor star CS29498-043, obtained with the Subaru
Telescope High Dispersion Spectrograph. We find its iron abundance is extremely
low ([Fe/H] = -3.7), placing it among the few stars known with [Fe/H] < -3.5,
while Mg and Si are significantly overabundant ([Mg/Fe] = +1.8, and [Si/Fe] =
+1.1) compared with stars of similar metallicity without carbon excess.
Overabundances of N and Al were also found. These characteristics are similar
to the carbon-rich, extremely metal-poor star CS22949-037. Though the sample is
small, our discovery of CS29498-043 suggests the existence of a class of
extremely metal-poor stars with large excesses of C, N, Mg, and Si.
