We prove that given a Noetherian ring R and a finitely generated N-mod
ule M, there exists a finite set of prime ideals Lambda in R such that
the depth or;ln arbitrary ideal I on M is determined by the height of
I module each of the primes in Lambda. As an application we answer a
question raised by the second author and V. Srinivas concerning m-adic
approximations of regular sequences in a local ring.