$.fn.codaSlider = function (options, scrollOptions) {
    var defaults = {
        horizontal : true,
        // etc 
        navigation : '.navigation a' // required
    };
    
    var settings = $.extend({}, defaults, options);
    
    var ret = this.each(function () {
        // do coda business
    };

    $.localScroll(scrollSettings); // where does scrollSettings derive from?
    return ret; 
}