Mount Sutro, a hill in San Francisco, is difficult to characterize. At 908 feet, it’s a very tall hill that comes close to being a small mountain. (Another 92 feet, and it would have that distinction.) Many hundreds of years ago it might have started life as a hybridized sand dune/chert rock outcropping: it sits to the south of the Great Sand Bank of the outer lands of the city where offshore gusts threw sand from west to east with impunity one hundred years ago.