Magento doesn't have default ''breadcrumbs'' on a cart or contact page. But there is a way to make the navigation for these pages more convenient.

In general, using the following way you can create any structure of bread crumbs on these pages. We will add ''crumds'' through xml.

So, let's take the cart page as an example, we need to update its layout.


Copy from base theme or open:</br>
app/design/frontend/default/your_theme/layout/checkout.xml
And add to the section checkout_cart_index:
<reference name="breadcrumbs">
            <action method="addCrumb">
                <crumbName>Main</crumbName>
                <crumbInfo>
                    <label>Main</label>
                    <title>Main</title>
                    <link>/</link>
                </crumbInfo>
            </action>
            <action method="addCrumb">
                <crumbName>Cart</crumbName>
                <crumbInfo>
                    <label>Cart</label>
                    <title>Cart</title>
                    <link>/checkout/cart/</link>
                </crumbInfo>
            </action>
        </reference> 
</pre>

This way we created the two-level structure of breadcrumbs on a cart page

If we want to change crumbs for CMS page, for example, to create the reference on parental page, we need to update the page layout in administrative panel the followinf way:


<reference name="root">
    <action method="unsetChild"><alias>breadcrumbs</alias></action>
     
    <block type="page/html_breadcrumbs" name="breadcrumbs" as="breadcrumbs">
        <action method="addCrumb">
            <crumbName>Main</crumbName>
            <crumbInfo><label>Main</label><title>Main</title><link>/</link></crumbInfo>
        </action>
        <action method="addCrumb">
            <crumbName>Parent Page</crumbName>
            <crumbInfo><label>Parent Page</label><title>Parent Page</title><link>/parent-page</link></crumbInfo>
        </action>
        <action method="addCrumb">
            <crumbName>Current Page</crumbName>
            <crumbInfo><label>Current Page</label><title>Current Page</title></crumbInfo>
        </action>
    </block>
</reference>
</pre>