Data type for serial during constraint?

Hiya,

I've never sent mail to a list before, so i hope i get it right =)

Downloaded and installed Postgres today for Slackware, for the first time.
Kudos to the PG team; we still can't believe it went so well.  We were up,
with JDBC access in about 20 minutes.  OH, a note about that... your docs
say Class.forName("postgresql.Driver") when the package created by your
makefile is really "org.postgresql.Driver" =)

Question tho':  I've specified a SERIAL primary key ("fooID") in some table
("t1").  From another table, I'd like to specify that primary key as a
foreign key.  I have to include a data type, but that will create another
sequencer for that field, which I would imagine is not the way root
intended?  for "t2"...

CREATE TABLE "T2" ( "t2ID" SERIAL, "fooID" ???? REFERENCES "t1" ("fooID") );

What goes where the '?' are?  Thanks in advance!

- Rob S.