Found this paperback at the local St. Vinnie's, which has a great book section. It's like walking into a bookstore all its own. I've been in bookstores smaller than the St. Vinnie book sections. Nicely organized and labeled sections and the prices are fantastic.
I just couldn't resist this one; cover and title both were simply too good to pass by. The blurb on the back, well, that cinched it!
Damon Draycot had won world renown as a historian and archeologist. .. His latest nine-month expedition was potholing in Texas. There were many miles of underground passages to explore ... what happens to him underground wold not be wished on any other man. Thereafter his life was never to be the same; dogged by an unfathomable curse that led him to shun his fellow creatures, this innocent expedition brought a nightmare of horror and evil into the light of day.
I assume one of the Dragon Dracos, or maybe Damon Draycot himself, were responsible for the state of the poor woman on the cover. Then again, it could have nothing to do with the story and just be a lurid cover for its own sake.
Paperback, New English Library, 1974