  Shubnikov de Haas oscillations for two well defined frequencies,
corresponding respectively to areas of 0.8 and 1.36% of the first Brillouin
zone (FBZ), were observed in single crystals of Na$_{0.3}$CoO$_2$. The
existence of Na superstructures in Na$_{0.3}$CoO$_2$, coupled with this
observation, suggests the possibility that the periods are due to the
reconstruction of the large Fermi surface around the $\Gamma$ point. An
alternative interpretation in terms of the long sought-after
$\epsilon_g^\prime$ pockets is also considered but found to be incompatible
with existing specific heat data.
