  The Per OB1 association, which contains the remarkable double cluster h and
chi Per, is unusual in not having a giant molecular cloud in its vicinity. We
show from Hipparcos data that the luminous members of this association exhibits
a bulk motion away from the galactic plane, such that their average velocity
increases with height above the galactic plane. We find HAeBe and T Tauri stars
towards probable remnant molecular clouds associated with Per OB1. These
star-forming regions lie well beyond the location of the luminous member stars
at heights of 280-400 pc above the galactic plane, far higher than that
previously found for embedded clusters. We argue that the observed motion of
the luminous member stars is most naturally explained if many formed from
molecular gas pushed and accelerated outwards by an expanding superbubble
driven presumably by stellar winds and perhaps also supernova explosions. A
large shell of atomic hydrogen gas and dust that lies just beyond the remnant
molecular clouds, believed to be driven by just such a superbubble, may
comprise the swept-up remains of the parental giant molecular cloud from which
this association formed. In support of this picture, we find a week trend for
the younger O star members to lie at higher galactic latitudes than the older
supergiant members. The star-forming regions located at even larger heights
above the galactic plane presumably correspond to more recent episodes of star
formation at or near the periphery of this superbubble.
