All of my default WordPress installs lately seem to configure the blog entries and the Read More button such that when the button is clicked the blog entry is loaded and the page “jumps” to the spot in the entry where the “more” button was located (a named anchor).
To change this default behaviour you need to add some code to your functions.php page. Here’s what the code you need to insert looks like:
function remove_more_link_scroll( $link ) {
$link = preg_replace( '|#more-[0-9]+|', '', $link );
return $link;
}
add_filter( 'the_content_more_link', 'remove_more_link_scroll' );
You can then style as you wish, regardless of the function modification above. Look for the class “more-link” in your template stylesheet.
The above tip, and more on customizing the Read More button in WordPress, check out this WordPress Codex link: http://codex.wordpress.org/Customizing_the_Read_More