  We present nuclear magnetic resonance (NMR) and nuclear quadrupole resonance
(NQR) measurements performed on single crystalline \ccag{}, a member of a
recently discovered family of heavy fermion materials Ce$_2M$Al$_7$Ge$_4$ ($M$
= Co, Ir, Ni, or Pd). Previous measurements indicated a strong Kondo
interaction as well as magnetic order below $T_M = 1.8$ K. Our NMR spectral
measurements show that the Knight shift $K$ is proportional to the bulk
magnetic susceptibility $\chi$ at high temperatures. A clear Knight shift
anomaly ($K \not\propto \chi$) is observed at coherence temperatures $T^* \sim
17.5$ K for $H_0 \parallel \hat{c}$ and 10 K for $H_0 \parallel \hat{a}$ at the
${}^{59}$Co site, and $T^* \sim 12.5$ K at the ${}^{27}$Al(3) site for $H_0
\parallel \hat{a}$ characteristic of the heavy fermion nature of this compound.
At high temperatures the ${}^{59}$Co NMR spin-lattice relaxation rate
$T_1^{-1}$ is dominated by spin fluctuations of the 4$f$ local moments with a
weak metallic background. The spin fluctuations probed by ${}^{59}$Co NMR are
anisotropic and larger in the basal plane than in the $c$ direction.
Furthermore, we find $(T_1TK)^{-1} \propto T^{-1/2}$ at the ${}^{59}$Co site as
expected for a Kondo system for $T > T^*$ and $T> T_K$. ${}^{59}$Co NQR \slrr{}
measurements at low temperatures indicate slowing down of spin fluctuations
above the magnetic ordering temperature $T_M \sim 1.8$ K. A weak ferromagnetic
character of fluctuations around $\mathbf{q}=0$ is evidenced by an increase of
$\chi T$ versus $T$ above the magnetic ordering temperature. We also find good
agreement between the observed and calculated electric field gradients at all
observed sites.
