From the ebook map, Underhill is located at approximately latitude 8.05 degrees and longitude -43.9 degrees, or about [here][1].

[![Underhill location (8.05,-43.9)][2]][2]

Ebook: ISBN: 9780553898279


  [1]: https://www.google.com/mars/#lat=8.05&lon=-43.9&zoom=7
  [2]: https://i.sstatic.net/53xW0ajH.png