The ornamental design for a chimneycover, as shown and described.
FIG. 1 is a top perspective view of a chimney cover, showing my new design;
FIG. 2 is a bottom perspective view thereof;
FIG. 3 is a side elevational view thereof, the opposite side being a mirror
image of that shown; and
FIG. 4 is a top perspective view of a chimney cover showing a second
embodiment of my new design, it being understood that the sole difference
resides in the shape of the cover being rectangular.