What bone does the Oracle bone in Oracle Bone Inscriptions refer to?

Oracle Bone Inscriptions is the earliest and most complete ancient script discovered by China. Oracle Bone Inscriptions mainly refers to Oracle Bone Inscriptions in Yin Ruins, also known as "Yin Ruins Characters" and "Yin Qi", which are carved on the bones of tortoise shells and beasts in Shang Dynasty. It was discovered in Xiaotun, Anyang, Henan at the end of 2008+09, and inherited the word-making method of Wen Tao. It was written by the royal family in the late Shang Dynasty (14 ~ 1 1 century) in China. After the demise of Shang Dynasty and the rise of Zhou Dynasty, Oracle Bone Inscriptions continued to be used for some time. The materials used for divination are mainly tortoise's abdominal shell, carapace and cattle's scapula. Usually, Oracle Bone Inscriptions for divination is prepared first.