Answer
Vertex: $(-1,4)$
Work Step by Step
The graphing form of a "sleeping" or sideways parabola is:
$x = a(y-k)² + h $
To find the vertex, take the inverse of k to get the y point of the vertex, and the h as itself for the x point of the vertex.
So in the equation:
$x=(y-4)^2-1$
The vertex is:
$(-1,4)$