1/6 Column, 6th column drops to new line in Genesis template

I have a child theme of the the stock Genesis. On a page that simple structured HTML, I decided to try and use the column classes. I set up a 6 column section like this:

`<div class="one-sixth start">


</div>
<div class="one-sixth">


</div>
<div class="one-sixth">


</div>
<div class="one-sixth">


</div>
<div class="one-sixth">


</div>
<div class="one-sixth">


</div>
'

I have not altered the CSS for page margins or padding.

The 6th column drops, even if the contents are small, like a 50px wide jpg. I removed any inline sizing, but it still drops.

The column is 680px with 60px left and right padding.

I'm also using a "one-half" pair of columns right above it in another section, and it works fine.

Here is a screenshot:

http://prntscr.com/5n3a7z

And here is a hastebin of the entire page because it's on local server right now:

http://hastebin.com/zeyeledina.xml