There are several things that probably require some attention.
-, <div> "" ul. ul li. , div li.
-, "div-itis". , , (?) div, , . .
-, : position: absolute, (, , , ) position: relative. , , , li position: relative.
, li
<header>
<h1><a href="index.html">Father Bart Gage</a></h1>
<ul>
<li><a id="about" href="#">ABOUT</a></li>
<li><a href="<!-- mailto:chris.gage@gmail.org -->">CONTACT</a></li>
<li>
<div class="dropdownwrapper">
<div class="dropdown">
<div class="dropbtn" onClick="return true">SCRIPTURE</div>
<div class="dropdown-content">
<a id="mark" href="#">Mark</a>
<a id="matthew" href="#">Matthew</a>
<a id="luke" href="#">Luke</a>
<a id="john" href="#">John</a>
</div>
</div>
</div>
</li>
</ul>
</header>
( , - . !)
<header>
<h1><a href="index.html">Father Bart Gage</a></h1>
<ul>
<li><a id="about" href="#">ABOUT</a></li>
<li><a href="<!-- mailto:chris.gage@gmail.org -->">CONTACT</a>
<li>
<div class="dropbtn" onClick="return true">SCRIPTURE</div>
<ul class="dropdown dropdown-content">
<li><a id="mark" href="#">Mark</a></li>
<li><a id="matthew" href="#">Matthew</a></li>
<li><a id="luke" href="#">Luke</a></li>
<li><a id="john" href="#">John</a></li>
</ul>
</li>
</ul>
</header>
Working Fiddle, .