[EBB Sightings] Sea birds over SF Bay

On Sunday afternoon I was out on the Berkeley pier
waiting for the Queen Mary to come into the bay when I
noticed a flock of 14 dark, gull-shaped birds flying
low over the water in front of the pier.  They banked
south and then again north at which point they were
directly overhead.  It's been a while since I've done
any pelagic birding so the details that I collected
are incomplete.  Never-the-less, this is what I
observed:

Dark brown back with no noticable markings.
Dark brown front with no noticable markings, but the
body slightly lighter than the under wings.
Size of a small to medium gull.
Tail was blunt/slightly rounded (not pointed or
notched)
Wing beat was fairly rapid and continuous.
A couple of individuals where calling in a short, high
pitch more delacte sounding than a gull.
I did not get a good look at the face or bill.
They were heading north east toward Cesar Chavez.

Any thoughts?