<!DOCTYPE HTML>
<style>
body {
    margin: 0
}

#scroller {
    position: relative;
    top: -150px;
    left: -50px;
    overflow: scroll;
    height: 300px;
    width: 300px;
    background-color: red;
}

#outer {
    position: absolute;
    top: 150px;
    left: 50px;
    width: 250px;
    height: 300px;
    overflow: hidden;
    background-color: blue;
}

#scrolled {
    height: 1000px;
    width: 250px;
    background-color: green;
}

#fixed {
    position: absolute;
    height: 100px;
    width: 100px;
    background-color: green;
    top: 250px;
    left: 50px;
}
</style>
<div id="outer">
    <div id="scroller">
        <div id="scrolled"></div>
    </div>
    <div id="fixed"></div>
</div>