John Leonard Riddell was a medical doctor, geologist, and botanist who traveled from New Orleans through Texas in 1839, surveying the Texas Hill Country for a group of businessmen searching for the lost San Saba silver mine. By joining the expedition, which of course did not find the mine, Riddell became the first trained scientist--preceding even Ferdinand Roemer--to visit the area of the Edwards Plateau and to provide a detailed description of the...