Navigation 3-bar icon displays, but doesn't produce dropdown menu

[tileman]

Newby question,
Just installed Foundation and added the top menu. The menu works, but the 3 bar icon that sits at far left in the top menu does not. Checked the JavaScript docs and Navigation Bar doc and believe I have loaded everything required. I put the site online at http://www.gantry.3wwork.com/ . I suspect that I am chasing the wrong solution. What makes that fly our menu work if not something in the js scripts?

Thanks in advance,
Blake...