I find the conclusion toward the end the article interesting:
“My analysis found that on the largest scale – casualty rates from battles grouped by underlying geology – all of these limestone-related factors appear to balance. That is, it didn’t really matter if a soldier was attacking across limestone, igneous and sedimentary rock, or terrain underlain by sand and clay, the casualty rates were consistently between 12 and 15 percent.”
Article from History News Network is here:
http://historynewsnetwork.org/article/162968