Three cave tombs were discovered in high cliffs during a region-wide heritage research program in 2014.
In the caves, scientists discovered human bones as well as infant corpses sealed in niches in the walls and covered by rocks.
Local Tashkurgans buried stillborn babies this way a few decades ago, according to Ai Tao from the Xinjiang Archeological Institute.
In 2013, a cluster of 102 tombs were discovered in nearby Kezilesu Kirgiz Autonomous Prefecture.
Scientists think ritualistic cave burial was practiced as far back as 4,000 years ago.