blocking course

from The Century Dictionary.

• noun In architecture, a plain member of square profile, either a single course of stone, or built up of bricks or the like to the required height, surmounting a cornice in the Roman and Renaissance styles. Its vertical face is usually in the plane of the wall or frieze below the cornice.

from the GNU version of the Collaborative International Dictionary of English.

• (Arch.) The finishing course of a wall showing above a cornice.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun architecture The finishing course of a wall showing above a cornice.