Css float menu not working properly

I create a float menu for my website. It is working good but have a 1 big problem. When I am scrolling the page, google adense and other plugin like author bio etc coming over to menu but not content.
this is my code below

/* my menu
-------------- */
.mymenu {
background: #444 url(-) repeat-x;
position: fixed;
color: #fff;
width: 100%;
float: left;
text-transform: uppercase;
box-shadow: 0px 0px 15px 0px #222;
clear: both;
display: block;
margin: 0 auto 6px;
}

.mymenu:hover {
text-decoration: underline;
}

.mymenu a {
color: #fff;
}

.mymenu a:hover {
text-decoration: underline;
}