reverse engineering alloy question - properties don't match up at all?

The About us page has 4 regions editable in the CMS editor:

1. Name
2. Page Description
3. Main Body
4. Large Conent area.

Looking at the pages properites, it is of type "Standard Page"

Looking in the source:  Models/Pages/StandardPage.cs has only 2 properties, and only one matches:

    public class StandardPage : SitePageData
    {
        [Display(
            GroupName = SystemTabNames.Content,
            Order = 310)]
        [CultureSpecific]
        public virtual XhtmlString MainBody { get; set; }
        [Display(
            GroupName = SystemTabNames.Content,
            Order = 320)]
        public virtual ContentArea MainContentArea { get; set; }
    }

And "Large Content Area" is missing, as is page name and description.

The page inherits from SitePageData, which has meta stuff, Teaser text (which I dont see anywhere in the UI), but also no "large conent area" etc.

Any suggestions?