We show that, given a chain 0 = P-0 subset of P-1 subset of ... subset
of P-n of prime ideals in a Noetherian domain R, there exist a finite
ly generated overring T of R and a saturated chain of primes in T cont
racting term by term to the given chain. We further show that there is
a discrete rank n valuation overring of R whose primes contract to th
ose of the given chain.