Chardonnay vs. Chablis

[chatnoir]

Thanks to both of you for being so prompt with your replies. I guess that I was more in error than I thought; however, I'm wondering why the difference in names (Chardonnay & Chablis), with respect to the French Chablis, if the wines are from the same grape ?

Also, how is one to tell from what grape a wine is made? This information is not always (frequently not) on the bottle.

Btw, the bartender was pouring from a Almaden labelled bottle.

Again, thanks!