There is a book at the Clarksville, TN Library called "From Yarberg to Yarbrough," which has our Yarbrough ancestors all the way back to when they came over from Denmark...If your Melvina was from the Montgomery/Stewart/Houston county areas, she may be listed there. It's in the reference-only section so you can't check it out but you CAN copy pages from it. I hope this helps! (Also, if she is listed there, you and I are more than likely related though I'm not sure how closely or distantly, as I still don't have all the information on my Yarbrough ancestors either (I do know that my great-great grandmother was Emma Eudorah Yarbrough).
If I can help in any way, please email me!