Let $F$ be a closed orientable surface of genus $g \geq 2$ and $C$ be a simple closed curve in $F$. Let $t_C$ denote a left-handed 
 Dehn twist about $C$. When $C$ is a nonseparating curve, D. Margalit and S. Schleimer showed the existence of such roots by finding 
 elegant examples of roots of $t_C$ whose degree is $2g + 1$ on a surface of genus $g + 1$. This motivated an earlier collaborative 
 work with D.McCullough in which we derived conditions for the existence of a root of degree $n$. We also showed that Margalit-Schleimer 
 roots achieve the maximum value of $n$ among all the roots for a given genus. Suppose that $C$ is a separating curve in $F$. First, 
 we derive algebraic conditions for the existence of roots in Mod$(F)$ of the Dehn twist $t_C$ about $C$. Finally, we show that if 
 $n$ is the degree of a root, then $n \leq 4g^2 +  2g$, and for $g \geq 10$, $n \leq \frac{16}{5}g^2+ 12g +\frac{45}{4}$.