Looking for good web sources for pond supplies.
 

I've got an image of a small pool in a stream that I saw as a child
that I wish to replicate as a pond. If you take a snapshot, the pool
was perhaps three feet wide with smooth medium size boulders
surrounding it. The bottom was sandy white. If I make it into a two
pool pond, I might be able create the modest cascade that fed the
pool.

So, I'm looking for a site that sells replica boulders for ponds and
one that will provide something more natural looking than the black
plastic tubs that you find at Home Depot. Thanks for any help.