What do I do with this?

Hi,

I've been baking for a while and have recently decided to make a foray
into Sourdough making sourdough bread. Well, a grocery store in my
town makes the best san francisco sourdough you've ever tasted (I live
in the bay area). I was talking to the baker today, and asked him if
he would be willing to share some starter with me. He said he would,
and gave me about a softball sized lump of sour smelling stuff
resembling bread dough almost. It is not smooth or runny at all. I'm
wondering...what is the difference between this "starter" and the
smooth creamy stuff I see pictures of on people's websites? Is this
just a ready made sponge, or what?


Also, should I feed this "starter" just like any other starter? The
baker recommended 1 cup water to 1 cup unbleached white flour...what
if I were to feed it 1/2 cup water and 1/2 cup flour? Would it just be
less "food"? Any other suggestions you have would be highly
appreciated!


Please excuse my ignorance. I'm just getting into sourdough, and want
to learn as much as I can.
Thanks for your time!