Oil pan gasket??

I have a 98 Rodeo with 94K and the oil pan gasket is leaking. I called to get a gasket and they said it was listed as having an upper and lower gasket. I've never seen a vehicle with two oil pan gaskets?? I have both gaskets ordered but was wondering what was up with the two gaskets and how hard is it to change them? Any info would be appreciated.

I'm planning on getting a repair manual but nobody has one local and I want to fix this this weekend.

Thx,
CB

On the 3.2/3.5, The lower pan gasket is for the small stamped steel pan that the drain plug is threaded into. The large gasket is for the lower aluminum block skirt. I'm not sure that one can be replaced easily. The little pan gasket should be easy to do.
G/luck
Joel

OK, I can see the leak in the bottom gasket and it looks like that one is fairly easy to change. Hopefully the top one is fine. Thanks for the quick response.

CB