William Morris Davis, a friend of Penck's father, criticized the theories Walther Penck outlined in "Die Piedmontflichen des südlichen Schwarzwald". Geographer Martin Simons claimed in 1962 that Davis misunderstood and mis-translated parts of the paper leaving a distorted view of Penck's ideas among later workers. Simons therefore does not consider Davis an adequate critic of Penck's work. Other factors detrimental to an understanding of Penck's ideas include his early death and his confusing writing style. Douglas Wilson Johnson, a coastal geomorphologist and staunch supporter of Davis, criticized Penck's theory harshly as: