Lest anyone else be led astray by
http://www.rockettheme.com/forum/gantry-solved-threads/126928-solved-where-are-the-missing-google-fonts
Let me point out that the methods detailed there do not apply to Gantry 4.x, even if you are on Joomla 2.5. (I know. It's a 2+ yr old thread. But it fooled me with "Solved".) If the admins could add the info below to the above thread, it might help someone.
webfonts.php no longer appears to exist in Gantry 4.x. The default elements affected by a Google Web Font selected in Template Manager are only h1 and h2. (An edited template copy of webfonts.php used to be a way to add more elements in the custom font.)
Read and follow the Gantry-framework.org documentation on Adding a Custom Font.
http://www.gantry-framework.org/documentation/joomla/tutorials/custom_font.md
I skipped the part about putting files in templates/.../fonts, selecting the font through the Template Manager instead. I added the web font to my Main Menu (the look I was going for) by putting one line of css in a custom css file as detailed on Gantry documentation:
.menutop li .item { font-family: 'Michroma', 'Helvetica', arial, serif; }