HELP:Volume generated("shell")

[buffgilville]

Find the volume generated when the region bounded by the graph of
f(x) = 4x^2
and the graph of
H(x) = 4
is rotated around the line y = -1

How do I solve this? How do I know if, when rotated, if the solid form a "shell" or a disc, or a washer?

[Tide]

Use Pappus' Theorem to find the volumes for each function then compute the difference.