The ornamental design for a bracket held semi-circular shelf, as shown and described.
FIG. 1 is a top plan view of a bracket held semi-circular shelf, wherein
the broken lines show visible environmental structure which forms no part
of the claimed design;
FIG. 2 is a front elevational view thereof, the rear elevational view there
appearing the same;
FIG. 3 is a bottom plan view thereof; and,
FIG. 4 is an end elevational view thereof, wherein the broken lines show
visible environmental structure which forms no part of the claimed design.