After 1912, Western researchers for a long time failed to identify any new stegosaurians, scientific interest in dinosaurs as whole being rather limited during the middle of the twentieth century. From the 1950s onwards, the geology of China was systematically surveyed in detail and infrastructural works led to a vast increase of digging activities in that country. This resulted in a new wave of Chinese stegosaurian discoveries, starting with "Chialingosaurus" in 1957. Chinese finds of the 1970s and 1980s included "Wuerhosaurus", "Tuojiangosaurus", "Chungkingosaurus", "Huayangosaurus", "Yingshanosaurus" and "Gigantspinosaurus". This increased the age range of good fossil stegosaurian material, as they represented the first relatively complete skeletons from the Middle Jurassic and the Early Cretaceous. Especially important was "Huayangosaurus", which provided unique information about the early evolution of the group.