The class of growing context-sensitive languages (GCSL) is
a naturally defined subclass of context-sensitive
languages whose membership problem is solvable in polynomial time.
GCSL and its deterministic counterpart called Church-Rosser
Languages CRL complement the Chomsky hierarchy in a natural way.
In this paper, the extension of GCSL} obtained by closures of this
class under boolean operations are investigated. We show that there
exists an infinite intersection hierarchy, answering an open problem
from [G.Buntrock, K.Lorys, On growing context-sensitive
languages, ICALP 1992, LNCS 623, 77--88.
Further, we compare expressive power of boolean
closures of GCSL, CRL, CFL and LOGCFL.
