  Quantum walks can be defined in two quite distinct ways: discrete-time and
continuous-time quantum walks (DTQWs and CTQWs). For classical random walks,
there is a natural sense in which continuous-time walks are a limit of
discrete-time walks. Quantum mechanically, in the discrete-time case, an
additional "coin space" must be appended for the walk to have nontrivial time
evolution. Continuous-time quantum walks, however, have no such constraints.
This means that there is no completely straightforward way to treat a CTQW as a
limit of DTQW, as can be done in the classical case. Various approaches to this
problem have been taken in the past. We give a construction for walks on
$d$-regular, $d$-colorable graphs when the coin flip operator is Hermitian:
from a standard DTQW we construct a family of discrete-time walks with a
well-defined continuous-time limit on a related graph. One can think of this
limit as a {\it coined} continuous-time walk. We show that these CTQWs share
some properties with coined DTQWs. In particular, we look at spatial search by
a DTQW over the 2-D torus (a grid with periodic boundary conditions) of size
$\sqrt{N}\times\sqrt{N}$, where it was shown \nocite{AAmbainis08} that a coined
DTQW can search in time $O(\sqrt{N}\log{N})$, but a standard CTQW
\nocite{Childs2004} takes $\Omega(N)$ time to search for a marked element. The
continuous limit of the DTQW search over the 2-D torus exhibits the
$O(\sqrt{N}\log{N})$ scaling, like the coined walk it is derived from. We also
look at the effects of graph symmetry on the limiting walk, and show that the
properties are similar to those of the DTQW as shown in \cite{HariKrovi2007}.
