What is continental shelf boundary?

Famous quotes containing the words shelf and/or boundary:

    The boy seemed to have fallen
    From shelf to shelf of someone’s rage.
    John Ashbery (b. 1927)

    Setting limits gives your child something to define himself against. If you are able to set limits without being overly intrusive or controlling, you’ll be providing him with a firm boundary against which he can test his own ideas.
    Stanley I. Greenspan (20th century)